MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Archives of Biochemistry and Biophysics' source. Sat, 20 Mar 2010 16:00:53 +0100 http://www.medworm.com/index.php?rid=3370989&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20227382%26dopt%3DAbstract Authors: Purdy MM, Holz-Schietinger C, Reich NO The human DNA methyltransferase 3A (DNMT3A) is essential for establishing DNA methylation patterns. Knowing the key factors involved in the regulation of mammalian DNA methylation is critical to furthering understanding of embryonic development and designing therapeutic approaches targeting epigenetic mechanisms. We observe substrate inhibition for the full length DNMT3A but not for its isolated catalytic domain, demonstrating that DNMT3A has a second binding site for DNA. Deletion of recognized domains of DNMT3A reveals that the conserved PWWP domain is necessary for substrate inhibition and forms at least part of the allosteric DNA binding site. The PWWP domain is demonstrated here to bind DNA in a cooperative manner with muM affinity. ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3370989 Thu, 11 Mar 2010 00:00:00 +0100 3370989 http://www.medworm.com/index.php?rid=3370988&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20227383%26dopt%3DAbstract Authors: Urushibata S, Hozumi K, Ishikawa M, Katagiri F, Kikkawa Y, Nomizu M Laminin alpha2 chain is specifically expressed in the basement membrane surrounding muscle and nerve. We screened biologically active sequences in the mouse laminin alpha2 chain G domain using 110 soluble peptides by the peptide-coated plate and the peptide-conjugated Sepharose bead assays. Fourteen peptides showed cell attachment activity in either or both assays. Cell attachment to A2G94 (YFDGTGFAKAVG) was inhibited by anti-integrin beta1 antibody, suggesting that the peptide promotes an integrin beta1-mediated cell attachment. Five peptides promoted PC12 cell neurite outgrowth. Since A2G10 (SYWYRIEASRTG) promoted strong cell attachment in the bead assay but showed slight activity in the plate assay, we conj... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3370988 Thu, 11 Mar 2010 00:00:00 +0100 3370988 http://www.medworm.com/index.php?rid=3370991&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20226754%26dopt%3DAbstract Authors: Stalmach A, Steiling H, Williamson G, Crozier A The intestinal absorption and metabolism of 385 mumol chlorogenic acids following a single intake of 200 mL of instant coffee by human volunteers with an ileostomy was investigated. HPLC-MS(3) analysis of 0-24 h post-ingestion ileal effluent revealed the presence of 274 +/- 28 mumol of chlorogenic acids and their metabolites accounting for 71 +/- 7 % of intake. Of the compounds recovered, 78% comprised parent compounds initially present in the coffee, and 22% were metabolites including free and sulfated caffeic and ferulic acids. Over a 24 h period after ingestion of the coffee, excretion of chlorogenic acid metabolites in urine accounted for 8 +/- 1 % of intake, the main compounds being ferulic acid-4-O-sulphate, caffeic acid-3-... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3370991 Wed, 10 Mar 2010 00:00:00 +0100 3370991 http://www.medworm.com/index.php?rid=3370990&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20226755%26dopt%3DAbstract Authors: Renck D, Ducati RG, Palma MS, Santos DS, Basso LA Uridine phosphorylase (UP) is a key enzyme in the pyrimidine salvage pathway, catalyzing the reversible phosphorolysis of uridine to uracil and ribose-1-phosphate (R1P). The human UP type 1 (hUP1) is a molecular target for the design of inhibitors intended to boost endogenous uridine levels to rescue normal tissues from the toxicity of fluoropyrimidine nucleoside chemotherapeutic agents, such as capecitabine and 5-fluorouracil. Here, we describe a method to obtain homogeneous recombinant hUP1, and present initial velocity, product inhibition, and equilibrium binding data. These results suggest that hUP1 catalyzes uridine phosphorolysis by a steady-state ordered bi bi kinetic mechanism, in which inorganic phosphate binds first f... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3370990 Wed, 10 Mar 2010 00:00:00 +0100 3370990 http://www.medworm.com/index.php?rid=3354664&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20214871%26dopt%3DAbstract In this study, we show that the protein levels of cyclin D1 and the CDK inhibitor, p21(CIP1), respond in a dose-dependent manner to the DNA damaging agent, 4-nitroquinoline 1-oxide (4NQO). Cyclin D1 responses were independent of p53 and resulted in a partial loss of Retinoblastoma protein phosphorylation. The differential responses of cyclin D1 and p21(CIP1) were associated with distinct cellular responses: in low dose treatments the cells recovered after a lag period whilst at medium and high doses, the cells died through seemingly distinct mechanisms. Our data suggest that the balance between cyclin D1 and p21(CIP1) following exposure to DNA damage may play a key role in determining the subsequent cellular responses. PMID: 20214871 [PubMed - as supplied by publisher] (Source: Archive... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3354664 Sat, 06 Mar 2010 00:00:00 +0100 3354664 http://www.medworm.com/index.php?rid=3354666&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20211593%26dopt%3DAbstract Authors: Battistuzzi G, Bellei M, Bortolotti CA, Sola M Peroxidases are heme enzymes found in bacteria, fungi, plants and animals, which exploit the reduction of hydrogen peroxide to catalyze a number of oxidative reactions, involving a wide variety of organic and inorganic substrates. The catalytic cycle of heme peroxidases is based on three consecutive redox steps, involving two high-valent intermediates (Compound I and Compound II), which perform the oxidation of the substrates. Therefore, the thermodynamics and the kinetics of the catalytic cycle are influenced by the reduction potentials of three redox couples, namely Compound I/Fe(3+), Compound I/Compound II and Compound II/Fe(3+). In particular, the oxidative power of heme peroxidases is controlled by the (high) reduction potent... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3354666 Thu, 04 Mar 2010 00:00:00 +0100 3354666 http://www.medworm.com/index.php?rid=3354665&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20211594%26dopt%3DAbstract Authors: Larsson AK, Shokeer A, Mannervik B Glutathione transferase (GST) displaying enhanced activity with the cytostatic drug 1,3-bis-(2-chloroethyl)-1-nitrosourea (BCNU) and structurally related alkylating agents was obtained by molecular evolution. Mutant libraries created by recursive recombination of cDNA coding for human and rodent Theta class GSTs were heterologously expressed in Escherichia coli and screened with the surrogate substrate 4-nitrophenethylbromide (NPB) for enhanced alkyltransferase activity. A mutant with a 70-fold increased catalytic efficiency with NPB, compared to human GST T1-1, was isolated. The efficiency in degrading BCNU had improved 170-fold, significantly more than with the model substrate NPB. The enhanced catalytic activity of the mutant GST was also ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3354665 Thu, 04 Mar 2010 00:00:00 +0100 3354665 http://www.medworm.com/index.php?rid=3347089&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20206594%26dopt%3DAbstract Authors: Gumiero A, Murphy EJ, Metcalfe CL, Moody PC, Raven EL The interactions of heme peroxidase enzymes with their substrates have been studied for many years, but only in the last decade or so has structural information begun to appear. This review looks at crystal structures for a number of heme peroxidases in complex with a number of (mainly organic) substrates. It examines the nature and location of the binding interaction, and explores functional similarities and differences across the family. PMID: 20206594 [PubMed - as supplied by publisher] (Source: Archives of Biochemistry and Biophysics) Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3347089 Wed, 03 Mar 2010 00:00:00 +0100 3347089 http://www.medworm.com/index.php?rid=3347090&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20206121%26dopt%3DAbstract Authors: Poulos TL The following is a brief review of peroxidase structural biology since the initial structure determination of cytochrome c peroxidase (CCP) 30 years ago. An emphasis will be placed on what CCP has taught us about peroxidase mechanisms, especially Compound I formation and electron transfer. PMID: 20206121 [PubMed - as supplied by publisher] (Source: Archives of Biochemistry and Biophysics) Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3347090 Tue, 02 Mar 2010 00:00:00 +0100 3347090 http://www.medworm.com/index.php?rid=3328049&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20193654%26dopt%3DAbstract Authors: Ellis HR The FMN-dependent two-component monooxygenase systems catalyze a diverse range of reactions. These two-component systems are composed of an FMN-reductase enzyme and a monooxygenase enzyme that catalyze the oxidation of various substrates. The role of the reductase is to supply reduced flavin to the monooxygenase enzyme, while the monooxygenase enzyme utilizes the reduced flavin to activate molecular oxygen. Unlike flavoproteins with a tightly or covalently bound prosthetic group, these enzymes catalyze the reductive and oxidative half-reaction on two separate enzymes. An interesting feature of these enzymes is their ability to transfer reduced flavin from the reductase to the monooxygenase enzyme. This review covers the reported mechanistic and structural properties o... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3328049 Fri, 26 Feb 2010 00:00:00 +0100 3328049 http://www.medworm.com/index.php?rid=3328048&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20193655%26dopt%3DAbstract Authors: Nurmemmedov E, Yengo RK, Ladomery MR, Thunnissen MM The zinc finger transcription factor Wilms Tumour protein (WT1) is known for its essential involvement in the development of the genitourinary system as well as of other organs and tissues. WT1 is capable of selectively binding either DNA or mRNA targets. A KTS insertion due to alternative splicing between the zinc fingers 3 and 4 and an unconventional zinc finger 1 are the unique features that distinguish WT1 from classical DNA-binding C(2)H(2)-type zinc finger proteins. The DNA binding characteristics of WT1 are well studied. Due to lack of information about its native RNA targets, no extensive research has been directed at how WT1 binds RNA. Using surface plasmon resonance, this study attempts to understand the binding beh... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3328048 Fri, 26 Feb 2010 00:00:00 +0100 3328048 http://www.medworm.com/index.php?rid=3328047&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20193656%26dopt%3DAbstract Authors: Hebert MD The Cajal body (CB) is a subnuclear domain that contains proteins and factors involved in a diverse range of activities including ribonucleoprotein maturation, histone gene transcription and telomerase assembly. Among these activities, the CBs' role in small nuclear ribonucleoprotein (snRNP) biogenesis is best characterized. Although CBs are found in plants, flies and mammals, not all cell types contain CBs. Rather, CBs are most prominent in transcriptionally active cells, such as cancer and neuronal cells. Many CB components, including the CB marker protein coilin, are phosphorylated in humans. The functional consequence of phosphorylation on CB assembly, activity and disassembly is largely unknown. Also unknown are the signaling pathways, kinases and phosphatases t... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3328047 Fri, 26 Feb 2010 00:00:00 +0100 3328047 http://www.medworm.com/index.php?rid=3328046&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20193657%26dopt%3DAbstract Authors: Xiong J, Fu G, Tao L, Zhu C Nitric oxide (NO) is involved in the regulation of multiple plant responses to a variety of abiotic and biotic stresses. Recently, an increasing number of articles have reported the effects of exogenous NO on alleviating heavy metal toxicity in plants. However, compared with the current understanding of the relationships between NO and other abiotic stresses, knowledge of the molecular and physiological mechanisms of NO in alleviating heavy metal toxicity is quite limited, and some results contradict one another. Therefore, to help clarify the roles of NO in heavy metal tolerance, it is valuable to review and discuss the recent advances on this research topic. In this mini-review, the latest advances in understanding the effects of heavy metals on e... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3328046 Fri, 26 Feb 2010 00:00:00 +0100 3328046 http://www.medworm.com/index.php?rid=3318976&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20188692%26dopt%3DAbstract In this study, we tested the effect of the amino acid sequences surrounding AF1 on the propensity of AF1 to gain structure when connected to DBD. Removal of amino acids between AF1 and DBD results in the formation of more ordered conformation in AF1. In addition, sequences flanking the AF1 may play an inhibitory role in AF1 activity. These results suggest a mechanism as to why certain GR isoforms with truncated N-terminal domains show altered transcriptional activity. PMID: 20188692 [PubMed - as supplied by publisher] (Source: Archives of Biochemistry and Biophysics) Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3318976 Wed, 24 Feb 2010 00:00:00 +0100 3318976 http://www.medworm.com/index.php?rid=3318975&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20188693%26dopt%3DAbstract Authors: Stoupi S, Williamson G, Drynan JW, Barron D, Clifford MN The catabolism by human fecal microflora of pure procyanidin B2 ((-)-epicatechin-4-->8-(-)-epicatechin) has been investigated using a static in vitro culture model. For the first time, twenty-four catabolites were detected by LC-MS(()(n)()) with M(r) greater than 290 indicating that they could not have formed from just one of the epicatechin units in the procyanidin structure. Structures have been assigned on the basis of the fragmentation in the ion trap mass spectrometer and with regard to catabolic pathways known to occur in fecal microorganisms. Twenty of these 'dimeric' catabolites produced fragment ions characteristic of flavanols and/or proanthocyanidins. One catabolite was identified tentatively as either 6 or... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3318975 Wed, 24 Feb 2010 00:00:00 +0100 3318975 http://www.medworm.com/index.php?rid=3318980&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19932080%26dopt%3DAbstract Authors: Zarai Z, Bacha AB, Horchani H, Bezzine S, Zouari N, Gargouri Y, Mejdoub H A marine snail digestive phospholipase A2 (mSDPL) was purified from delipidated hepatopancreas. Unlike known digestive phospholipases A2, which are 14 kDa proteins, the purified mSDPL has a molecular mass of about 30 kDa. It has a specific activity of about 180 U/mg measured at 50 degrees C and pH 8.5 using phosphatidylcholine liposomes as a substrate in the presence of 4 mM NaTDC and 6mM CaCl2. The N-terminal amino-acid of the purified mSDPL does not share any homology with known phospholipases. Moreover, the mSDPL exhibits hemolytic activity in intact erythrocytes and can penetrate phospholipid monolayers at high surface pressure, comparable to snake venom PLA2. These observations suggest that mSDPL co... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3318980 Mon, 15 Feb 2010 00:00:00 +0100 3318980 http://www.medworm.com/index.php?rid=3318979&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20004171%26dopt%3DAbstract Authors: Masson P, Lockridge O Butyrylcholinesterase is a promiscuous enzyme that displays complex kinetic behavior. It is toxicologically important because it detoxifies organophosphorus poisons (OP) by making a covalent bond with the OP. The OP and the butyrylcholinesterase are both inactivated in the process. Inactivation of butyrylcholinesterase has no adverse effects. However, inactivation of acetylcholinesterase in nerve synapses can be lethal. OP-inhibited butyrylcholinesterase and acetylcholinesterase can be reactivated with oximes provided the OP has not aged. Strategies for preventing the toxicity of OP include (a) treatment with an OP scavenger, (b) reaction of non-aged enzyme with oximes, (c) reactivation of aged enzyme, (d) slowing down aging with peripheral site ligands, ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3318979 Mon, 15 Feb 2010 00:00:00 +0100 3318979 http://www.medworm.com/index.php?rid=3318978&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20005865%26dopt%3DAbstract We report that heme not only displays high binding affinity to the aggregates of crystallin, but also it is effectively able to interfere with this type of aggregation. In the present study, the influence of heme concentration on the crystallin fibrillogenesis was also investigated and experimental evidence of heme's prevention of crystallin aggregation was provided with the help of spectroscopic measurements. Significantly, using alpha-crystallin-based experimental system, we proposed that elevated levels of peroxidase activity may have a determinant role in amyloid pathogenesis. The substantial peroxidase activity of "crystallin aggregate-heme" may partially explain the acceleration of oxidative damage in several amyloid-affected neurodegenerative diseases. The present study also suggest... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3318978 Mon, 15 Feb 2010 00:00:00 +0100 3318978 http://www.medworm.com/index.php?rid=3318977&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20005866%26dopt%3DAbstract Authors: McDonald CB, Seldeen KL, Deegan BJ, Bhat V, Farooq A Allostery has evolved as a form of local communication between interacting protein partners allowing them to quickly sense changes in their immediate vicinity in response to external cues. Herein, using isothermal titration calorimetry (ITC) in conjunction with circular dichroism (CD) and macromolecular modeling (MM), we show that the binding of Grb2 adaptor--a key signaling molecule involved in the activation of Ras GTPase--to its downstream partners Sos1 guanine nucleotide exchange factor and Gab1 docker is under tight allosteric regulation. Specifically, our findings reveal that the binding of one molecule of Sos1 to the nSH3 domain allosterically induces a conformational change within Grb2 such that the loading of a seco... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3318977 Mon, 15 Feb 2010 00:00:00 +0100 3318977 http://www.medworm.com/index.php?rid=3284583&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20159007%26dopt%3DAbstract Authors: Oppenheimer M, Pierce BS, Crawford JA, Ray K, Helm RF, Sobrado P Tetrahydrofuran monooxygenase (Thm) catalyzes the NADH-and oxygen-dependent hydroxylation of tetrahydrofuran to 2-hydroxytetrahydrofuran. Thm is composed of a hydroxylase enzyme, a regulatory subunit, and an oxidoreductase named ThmD. ThmD was expressed in E. coli as a fusion to maltose binding protein (MBP) and isolated to homogeneity after removal of the MBP. Purified ThmD contains covalently bound FAD, [2Fe-2S] center, and was shown to use ferricyanide, cytochrome c, 2,6-dichloroindophenol, and to a lesser extent, oxygen as surrogate electron acceptors. ThmD displays 160-fold preference for NADH over NADPH and functions as a monomer. The flavin-binding domain of ThmD (ThmD-FD) was purified and characterized. T... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3284583 Sat, 13 Feb 2010 00:00:00 +0100 3284583 http://www.medworm.com/index.php?rid=3276682&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20153712%26dopt%3DAbstract Authors: Lara LS, Vives D, Correa JS, Cardozo FP, Marques-Fernades MF, Lopes AG, Caruso-Neves C We showed previously that angiotensin-(1-7) [Ang-(1-7)] reversed stimulation of proximal tubule Na(+)-ATPase promoted by angiotensin II (Ang II) through a d-ala(7)-Ang-(1-7) (A779)-sensitive receptor. Here we investigated the signaling pathway coupled to this receptor. According to our data, Ang-(1-7) produces a MAS-mediated reversal of Ang II-stimulated Na(+)-ATPase by a Gs/PKA pathway because: (1) the Ang-(1-7) effect is reversed by GDPbetaS, an inhibitor of trimeric G protein and Gs polyclonal antibody. Cholera toxin, an activator of Gs protein, mimicked it; (2) in the presence of Ang II, Ang-(1-7) increased the PKA activity 10-fold; (3) the peptide inhibitor of PKA blocked the Ang-(1-7) ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3276682 Thu, 11 Feb 2010 00:00:00 +0100 3276682 http://www.medworm.com/index.php?rid=3276681&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20153713%26dopt%3DAbstract Authors: Costanzo LD, Ilies M, Thorn KJ, Christianson DW Human arginase I is a binuclear manganese metalloenzyme that catalyzes the hydrolysis of L-arginine to generate L-ornithine and urea. We demonstrate that N-hydroxy-L-arginine (NOHA) binds to this enzyme with K(d) = 3.6 muM, and nor-N-hydroxy-L-arginine (nor-NOHA) binds with K(d) = 517 nM (surface plasmon resonance) or K(d) approximately 50 nM (isothermal titration calorimetry). Crystals of human arginase I complexed with NOHA and nor-NOHA afford 2.04 A and 1.55 A resolution structures, respectively, which are significantly improved in comparison with previously determined structures of the corresponding complexes with rat arginase I. Higher resolution structures clarify the binding interactions of the inhibitors. Finally, the cry... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3276681 Thu, 11 Feb 2010 00:00:00 +0100 3276681 http://www.medworm.com/index.php?rid=3276680&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20153714%26dopt%3DAbstract Authors: Bhattacharjee A, Majumdar U, Maity D, Sarkar TS, Goswami AM, Sahoo R, Ghosh S Nitrosative stress has various pathophysiological implications. We here present a detailed characterization on the effect of nitrosative stress in Saccharomyces cerevisiae wild type (Y190) and its isogenic flavohemoglobin mutant (Deltayhb1) strain grown in presence of non fermentable carbon source. On addition of sub toxic dose of nitrosating agent both the strains showed microbiostatic effect. Cellular respiration was found to be significantly affected in both the strains in presence sodium nitroprusside. Although there was no alteration in mitochondrial permeability potential changes and reactive oxygen species production in both the strains but the cellular redox status is differentially regulated... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3276680 Thu, 11 Feb 2010 00:00:00 +0100 3276680 http://www.medworm.com/index.php?rid=3276679&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20153715%26dopt%3DAbstract Authors: Klaus V, Hartmann T, Gambini J, Graf P, Stahl W, Hartwig A, Klotz LO Selected biological effects of 1,4-naphthoquinone, menadione (2-methyl-1,4-naphthoquinone) and structurally related quinones from natural sources - the 5-hydroxy-naphthoquinones juglone, plumbagin and the 2-hydroxy-naphthoquinones lawsone and lapachol - were studied in human keratinocytes (HaCaT). 1,4-naphthoquinone and menadione as well as juglone and plumbagin were highly cytotoxic, strongly induced reactive oxygen species (ROS) formation and depleted cellular glutathione. Moreover, they induced oxidative DNA base damage and accumulation of DNA strand breaks, as demonstrated in an alkaline DNA unwinding assay. Neither lawsone nor lapachol (up to 100 muM) were active in any of these assays. Cytotoxic and oxi... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3276679 Thu, 11 Feb 2010 00:00:00 +0100 3276679 http://www.medworm.com/index.php?rid=3276684&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20153287%26dopt%3DAbstract Authors: Bailey LM, Wallace JC, Polyak SW Holocarboxylase synthetase (HCS) governs the cellular fate of the essential micronutrient biotin (Vitamin H or B7). HCS is responsible for attaching biotin onto the biotin-dependent enzymes that reside in the cytoplasm and mitochondria. Evidence for an alternative role, viz the regulation of gene expression, has also been reported. Recent immunohistochemical studies reported HCS is primarily nuclear, inconsistent with the location of HCS activity. Improved understanding of biotin biology demands greater knowledge about HCS. Here we investigated the localisation of HCS and its isoforms. Three variants were observed that differ at the N-terminus. All HCS isoforms were predominantly non-nuclear, consistent with the distribution of biotin protein l... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3276684 Wed, 10 Feb 2010 00:00:00 +0100 3276684 http://www.medworm.com/index.php?rid=3276683&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20153288%26dopt%3DAbstract Authors: Cizas P, Budvytyte R, Morkuniene R, Moldovan R, Broccio M, Lösche M, Niaura G, Valincius G, Borutaite V The link between the size of soluble amyloid beta Abeta oligomers and their toxicity to rat cerebellar granule cells (CGC) was investigated. Variation in conditions during in vitro oligomerization of Abeta1(-42) resulted in peptide assemblies with different particle size as measured by atomic force microscopy and confirmed by the dynamic light scattering and fluorescence correlation spectroscopy. Small oligomers of Abeta1(-42) with a mean particle z-height of 1-2 nm exhibited propensity to bind to the phospholipid vesicles and they were the most toxic species that induced rapid neuronal necrosis at submicromolar concentrations whereas the bigger aggregates (z-height abo... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3276683 Wed, 10 Feb 2010 00:00:00 +0100 3276683 http://www.medworm.com/index.php?rid=3255031&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20138019%26dopt%3DAbstract In this study, we demonstrated that both the mRNA and protein levels of beta2- and beta3-AR are up-regulated following osteogenesis of mouse MSCs. We also established that beta-AR agonists negatively while antagonists positively affect MSC osteogenesis. Both the beta2- and beta3-AR are involved in MSC osteogenesis, but beta2-AR is dominant. The effect of beta-ARs on MSC osteogenesis is at least partly mediated via the cAMP/PKA signaling. These findings suggest that MSC is also a target for beta-adrenergic regulation and beta-adrenergic signaling plays a role in MSC osteogenesis. PMID: 20138019 [PubMed - as supplied by publisher] (Source: Archives of Biochemistry and Biophysics) Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3255031 Tue, 02 Feb 2010 00:00:00 +0100 3255031 http://www.medworm.com/index.php?rid=3255030&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20138020%26dopt%3DAbstract Authors: Kimura T, Taniguchi S, Niki I We have recently reported that GDP-bound Rab27a regulates endocytosis of the insulin secretory membrane via its binding to coronin 3, an actin-binding protein. The aim of this study was to examine the participation of actin assembly in the Rab27a-dependent regulation of endocytosis using a pancreatic beta cell line, MIN6. Coronin 3 promoted F-actin bundling only in the presence of GDP-Rab27a. This effect was independent of coronin-3-binding to the actin-related proteins 2 and 3 (Arp2/3). Uptake of anti-phogrin-lumen antibody into MIN6 was inhibited by anti-coronin-3-C antibody which recognizes the actin-binding site. This inhibition was also observed with coronin-3-R28D, which lacks in actin binding. These results suggest that coronin 3 is a genui... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3255030 Tue, 02 Feb 2010 00:00:00 +0100 3255030 http://www.medworm.com/index.php?rid=3244647&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20122893%26dopt%3DAbstract Authors: Belisario DC, Rocafull MA, Del Castillo JR Distal colon absorbs K(+) through a Na(+)-independent, ouabain-sensitive H(+)/K(+)-exchange, associated to an apical ouabain-sensitive H(+)/K(+)-ATPase. Expression of HKalpha2, gene associated with this ATPase, induces K(+)-transport mechanisms, whose ouabain susceptibility is inconsistent. Both ouabain-sensitive and ouabain-insensitive K(+)-ATPase activities have been described in colonocytes. However, native H(+)/K(+)-ATPases have not been identified as unique biochemical entities. Herein, a procedure to purify ouabain-sensitive H(+)/K(+)-ATPase from guinea-pig distal colon is described. H(+)/K(+)-ATPase is Mg(2+)-dependent and activated by K(+), Cs(+) and NH(4)(+) but not by Na(+) or Li(+), independently of K(+)-accompanying anion.... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3244647 Fri, 29 Jan 2010 00:00:00 +0100 3244647 http://www.medworm.com/index.php?rid=3244645&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20122894%26dopt%3DAbstract In this study, we examined whether ascorbic acid (AA) and dehydroascorbic acid (DHA), the oxidized form of AA, levels in tissues regulate the AA transporters, sodium-dependent vitamin C transporters (SVCT) 1 and SVCT2 and DHA transporters, glucose transporter (GLUT) 1, GLUT3, GLUT4 mRNA by using senescence marker protein-30 (SMP30)/gluconolactonase (GNL) knockout (KO) mice. These mice are incapable of synthesizing AA in vivo. AA depletion enhanced SVCT1 and SVCT2 mRNA expression in the liver and SVCT1 and GLUT4 mRNA expression in the small intestine, but not in the cerebrum or kidney. Next, we examined the actual impact of AA uptake by using primary cultured hepatocytes from SMP30/GNL KO mice. In the AA-depleted hepatocytes from SMP30/GNL KO mice, AA uptake was significantly greater than i... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3244645 Fri, 29 Jan 2010 00:00:00 +0100 3244645 http://www.medworm.com/index.php?rid=3236652&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20117072%26dopt%3DAbstract Authors: Da Silva D, Zancan P, Coelho WS, Gomez LS, Sola-Penna M The present work describes the effects of metformin on hexokinase (HK) and phosphofructokinase (PFK) activities and localization in different tissues from streptozotocin-induced diabetic mice. Diabetic mice present lower HK and PFK activities (50 %) in skeletal muscle, liver and adipose tissue, as compared with control (P < 0.05). Treatment with 250 mg/kg metformin reverses this pattern of enzyme inhibition with concomitant reversal of hyperglycemia and hypolactacidemia. Furthermore, the treatment increases the cytoskeleton-associated PFK activity in skeletal muscle; this activity has been described as an important mechanism for the enzyme activation. This effect might be due to the increased phosphorylation of serine ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3236652 Thu, 28 Jan 2010 00:00:00 +0100 3236652 http://www.medworm.com/index.php?rid=3236651&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20117073%26dopt%3DAbstract Authors: Vaaje-Kolstad G, Farkaš V, Fincher GB, Hrmova M Three barley xyloglucan endotransglycosylases (HvXETs), known as xyloglucan xyloglucosyl transferases (EC 2.4.1.207), were subjected to kinetic and computational docking studies. The k(cat)(.)K(m)(-1) values with the reduced [(3)H]-labelled XXXG, XXLG/XLXG and XLLG acceptor substrates were 0.02.10(-2), 0.1.10(-2) and 3.2.10(-2) s(-1).muM(-1), while the K(m) constants were 10.6, 8.6 and 5.3 mM, obtained for HvXET3, HvXET4 and HvXET6, respectively. Docking of XLLG in acceptor-binding regions revealed that at least two conformational states were likely to participate in all isoforms. The assessments of kinetic and computational data indicated that the disposition of aromatic residues at the entrance to the active sites and the... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3236651 Thu, 28 Jan 2010 00:00:00 +0100 3236651 http://www.medworm.com/index.php?rid=3219427&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20102698%26dopt%3DAbstract Authors: Hida K, Won SY, Pasquale GD, Hanes J, Chiorini JA, Ostermeier M Gene therapy vectors based on adeno-associated virus (AAV) have shown much promise in clinical trials for the treatment of a variety of diseases. However, the ability to manipulate and engineer the viral surface for enhanced efficiency is necessary to overcome such barriers as pre-existing immunity and transduction of non-target cells that currently limit AAV applications. Although single amino acid changes and peptide insertions at select sites have been explored previously, the tolerance of AAV to small deletions and tandem duplications of sequence has not been globally addressed. Here, we have generated a large, diverse library of >10(5) members containing deletions and tandem duplications throughout the vir... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3219427 Sat, 23 Jan 2010 00:00:00 +0100 3219427 http://www.medworm.com/index.php?rid=3219426&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20102699%26dopt%3DAbstract We report the isolation and structure-function relationship of a 23 kDa metalloproteinase named atroxlysin-I from the venom of the Peruvian Bothrops atrox (Jergón). Atroxlysin is a P-I metalloproteinase and contains 204 residues. Its proteolytic activity towards dimethylcasein is enhanced by Ca(+2) but inhibited by EDTA, dithiothreitol, excessive Zn(+2) and alpha2-macroglobulin. Unlike other structurally homologous P-I metalloproteinases, atroxlysin-I causes hemorrhages. To examine its hemorrhagic activity mechanistically, we studied its function in vitro and in vivo. It cleaved the Ala(14)-Leu(15) and Tyr(16)-Leu(17) bonds in oxidized insulin B-chain and specifically hydrolyzed the alpha-chains of fibrin(ogen) in a dose- and time-dependent manner. Atroxlysin-I cleaved plasma fibronec... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3219426 Sat, 23 Jan 2010 00:00:00 +0100 3219426 http://www.medworm.com/index.php?rid=3212789&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20097153%26dopt%3DAbstract In conclusion, closure of VDAC appears to impede the efflux of superoxide anions from the IMS, resulting in an increased steady-state level of O(2)(*)(-), which causes an internal oxidative stress and sensitizes mitochondria toward the Ca(2+)-induced MPT. PMID: 20097153 [PubMed - as supplied by publisher] (Source: Archives of Biochemistry and Biophysics) Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3212789 Thu, 21 Jan 2010 00:00:00 +0100 3212789 http://www.medworm.com/index.php?rid=3186248&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20079707%26dopt%3DAbstract Authors: Lindberg D, Ahmad S, Widersten M Epoxide hydrolase, StEH1, shows hysteretic behavior in the catalyzed hydrolysis of trans-2-methylstyrene oxide (2-MeSO). Linkage between protein structure dynamics and catalytic function was probed in mutant enzymes in which surface-located salt-bridging residues were substituted. Salt bridges at the interface of the alpha/beta-hydrolase fold core and lid domains, as well as between residues in the lid domain, between Lys(179)-Asp(202), Glu(215)-Arg(41) and Arg(236)-Glu(165) were disrupted by mutations, K179Q, E215Q, R236K and R236Q. All mutants displayed enzyme activity with styrene oxide (SO) and 2-MeSO when assayed at 30 degrees C. Disruption of salt bridges altered the rates for isomerization between distinct Michaelis complexes, with (1R,2... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3186248 Wed, 13 Jan 2010 00:00:00 +0100 3186248 http://www.medworm.com/index.php?rid=3177846&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20074546%26dopt%3DAbstract Authors: Anbazhagan V, Cymer F, Schneider D The exact nature of membrane protein folding and assembly is not understood in detail yet. Addition of SDS to a membrane protein dissolved in mild, non-polar detergent results in formation of mixed micelles and in subsequent denaturation of higher ordered membrane protein structures. The exact nature of this denaturation event is, however, enigmatic, and separation of an individual helix pair in mixed micelles has also not been reported yet. Here we followed unfolding of the human glycophorin A transmembrane helix dimer in mixed micelles by fluorescence spectroscopy. Energy transfer between differently labelled glycophorin A transmembrane helices decreased with increasing SDS mole fractions albeit without modifying the helicity of the peptide... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3177846 Mon, 11 Jan 2010 00:00:00 +0100 3177846 http://www.medworm.com/index.php?rid=3172307&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20064484%26dopt%3DAbstract Authors: Fukuzono S, Kato T, Fujita H, Watanabe N, Kitagawa S We studied the effect of G-CSF on TLR agonist-induced cytokine production in human neutrophils. Human neutrophils produced IL-8 and TNF-alpha in response to stimulation with TLR agonists such as LPS and N-palmitoyl-S-[2,3-bis(palmitoyloxy)-(2RS)- propyl]-(R)-cysteinyl-seryl-(lysyl)(3)-lysine. This response was dependent on activation of ERK, p38, and PI3K, but not JNK. TLR agonist-induced cytokine production in neutrophils was inhibited by G-CSF, whereas it was enhanced by GM-CSF, and GM-CSF-mediated enhancement was attenuated by G-CSF. G-CSF and GM-CSF did not affect TLR agonist-induced phosphorylation of ERK, p38, JNK, Akt, and IkappaBalpha. STAT3 activation was much greater in G-CSF-stimulated neutrophils than that in GM-... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3172307 Fri, 08 Jan 2010 00:00:00 +0100 3172307 http://www.medworm.com/index.php?rid=3164287&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20060803%26dopt%3DAbstract Authors: Wang Z, Shi Q, Yan R, Liu G, Zhang W, Dai K There are evidence that both a disintegrin and metalloproteinase 17 (ADAM17) and calpain are involved in platelet glycoprotein (GP) Ibalpha ectodomain cleavage. However, the relationship between the two enzymes in the shedding process remains unclear. Here we show that calcium ionophore A23187- and alpha-thrombin-induced GPIbalpha shedding is completely inhibited by the metalloproteinase inhibitor GM6001, whereas is only partially inhibited by calpain inhibitors. Calpain activator dibucaine-induced GPIbalpha shedding was completely inhibited by both metalloproteinase and calpain inhibitors. On the other hand, calpain inhibitors did not inhibit GPIbalpha shedding induced by the reagents that specifically activate ADAM17. Furthermore, ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3164287 Thu, 07 Jan 2010 00:00:00 +0100 3164287 http://www.medworm.com/index.php?rid=3164286&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20060804%26dopt%3DAbstract Authors: To MS, Aromataris EC, Castro J, Roberts ML, Barritt GJ, Rychkov GY Uncouplers of mitochondrial oxidative phosphorylation, including carbonilcyanide p-triflouromethoxyphenylhydrazone (FCCP) and carbonilcyanide m-cholorophenylhydrazone (CCCP), are widely used in experimental research investigating the role of mitochondria in cellular function. Unfortunately, it is very difficult to interpret the results obtained in intact cells using FCCP and CCCP, as these agents not only inhibit mitochondrial potential, but may also affect membrane potential and cell volume. Here we show by whole-cell patch clamping that in primary rat hepatocytes and H4IIE liver cells, FCCP induced large proton currents across the plasma membrane but did not activate any other observable conductance. In intac... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3164286 Thu, 07 Jan 2010 00:00:00 +0100 3164286 http://www.medworm.com/index.php?rid=3164285&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20060805%26dopt%3DAbstract Authors: Yadav RK, Dolai S, Pal S, Adak S Architecture of hemoprotein is solely responsible for different nature of heme coordination. Here we report that substitution of the acidic surface residue Glu226 to Ala in ascorbate peroxidase from L. major alters the 5 coordinate high spin (5cHS) to a 6 coordinate low spin (6cLS) form at pH 7.5. Using UV-Visible spectrophotometry, we show that the sixth ligand of heme in Glu226Ala at pH 7.5 is hydroxo. When the pH is decreased to 5.5, a new species of Glu226Ala appeared that had a spectrum characteristic of a 6cHS derivative. Stopped flow spectrophotometric techniques revealed that characteristics of compound I was not seen in the Glu226Ala in presence of H(2)O(2). Similarly guaiacol, ascorbate and ferrocytochrome c oxidation rate was 10(3) o... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3164285 Thu, 07 Jan 2010 00:00:00 +0100 3164285 http://www.medworm.com/index.php?rid=3164288&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20060377%26dopt%3DAbstract Authors: Borovikov YS, Shelud'ko NS, Avrova SV The effect of twitchin, a thick filament protein of molluscan muscles, on actin-myosin interaction at several mimicked sequential steps of the ATPase cycle was investigated using fluorescent probes specifically bound to Cys707 of myosin subfragment-1 and Cys374 of actin incorporated into ghost muscle fibres. The multi-step changes in mobility and spatial arrangement of myosin SH1 helix and actin subdomain-1 during the ATPase cycle have been revealed. For the first time, the inhibition of movement of myosin SH1 helix and actin subdomain-1 during the ATPase cycle and the decrease in the myosin head and actin affinity in the presence of unphosphorylated twitchin have been demonstrated. Phosphorylation of twitchin by the catalytic subunit of p... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3164288 Wed, 06 Jan 2010 00:00:00 +0100 3164288 http://www.medworm.com/index.php?rid=3139550&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20045390%26dopt%3DAbstract Authors: Hwang SK, Nishi A, Satoh H, Okita TW Previous genetic studies have indicated that the type L alpha-glucan phosphorylase (Pho1) has an essential role during the initiation process of starch biosynthesis during rice seed development. To gain insight into its role in starch metabolism, we characterized the enzymatic properties of the Pho1 recombinant form. Pho1 has significantly higher catalytic efficiency toward both linear and branched alpha-glucans in the synthesis direction than in the degradation direction with equilibrium constants for the various substrates ranging from 13 to 45. Pho1 activity is strongly inhibited by its own reaction product (Pi) in the synthesis reaction (K(i) = 0.69 mM) when amylopectin is the primer substrate, but this inhibition is less pronounced (K(... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3139550 Wed, 30 Dec 2009 00:00:00 +0100 3139550 http://www.medworm.com/index.php?rid=3139549&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20045391%26dopt%3DAbstract Authors: Pyatibratov MG, Tolkatchev D, Plamondon J, Xu P, Ni F, Kostyukova AS Angiogenin is a potent inducer of angiogenesis, a process of blood vessel formation. It interacts with endothelial and other cells and elicits a wide range of cellular responses including migration, proliferation, and tube formation. One important target of angiogenin is endothelial cell-surface actin and their interaction might be one of essential steps in angiogenin-induced neovascularization. Based on earlier indications that angiogenin promotes actin polymerization, we studied the binding interactions between angiogenin and actin in a wide range of conditions. We showed that at subphysiological KCl concentrations, angiogenin does not promote, but instead inhibits polymerization by sequestering G-actin. At... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3139549 Wed, 30 Dec 2009 00:00:00 +0100 3139549 http://www.medworm.com/index.php?rid=3137143&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20043865%26dopt%3DAbstract Authors: Jernerén F, Hoffmann I, Oliw EH Oxygenation of linoleic acid by Aspergillus terreus was studied with LC-MS/MS. 9(R)-Hydroperoxy-10(E),12(Z)-octadecadienoic acid (9R-HpODE) was identified along with 10(R)-hydroxy-8(E),12(Z)-octadecadienoic acid and variable amounts of 8(R)-hydroxy-9(Z),12(Z)-octadecadienoic acid. 9R-HpODE was formed from [11S-(2)H]18:2n-6 with loss of the deuterium label, suggesting antarafacial hydrogen abstraction and oxygenation. Two polar metabolites were identified as 9-hydroxy-10-oxo-12(Z)-octadecenoic acid (alpha-ketol) and 13-hydroxy-10-oxo-11(E)-octadecenoic acid (gamma-ketol), likely formed by spontaneous hydrolysis of an unstable allene oxide, 9(R),10-epoxy-10,12(Z)-octadecadienoic acid. alpha-Linolenic acid and 20:2n-6 were oxidized to hydroper... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3137143 Mon, 28 Dec 2009 00:00:00 +0100 3137143 http://www.medworm.com/index.php?rid=3129992&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20035707%26dopt%3DAbstract Authors: Kar P, Samanta K, Shaikh S, Chowdhury A, Chakraborti T, Chakraborti S Calpain system is generally known to be comprised of three molecules: two Ca(2+)-dependent proteases: mu- and m-calpains, and their endogenous inhibitor, calpastatin. While calpains have previously been considered as the cytoplasmic enzymes, research in the recent past demonstrated that mu-calpain, m-calpain and calpain 10 are present in mitochondria, which play important roles in a variety of pathophysiological conditions including necrotic and apoptotic cell death phenomena. Although a number of original research articles on mitochondrial calpain system are available, yet to the best of our knowledge, a precise review article on mitochondrial calpain system has, however, not been available. This review out... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3129992 Tue, 22 Dec 2009 00:00:00 +0100 3129992 http://www.medworm.com/index.php?rid=3129991&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20035708%26dopt%3DAbstract Authors: Sebai H, Ristorcelli E, Sbarra V, Hovsepian S, Fayat G, Aouani E, Lombardo D Lipopolysaccharides (LPS) are major components of the cell wall of gram negative bacteria implicated in the pathogenesis of bacterial infection. Resveratrol is a polyphenolic phytoalexin exhibiting antioxidant and anti-inflammatory properties. We investigated the protective effects of this natural compound on LPS-induced proinflammatory effect using non myeloid AR42J pancreatic cells. We found that LPS dose-dependently increased extracellular malondialdehyde (MDA) and nitric oxide without affecting their intracellular level whereas resveratrol abolished all these deleterious effects. LPS increased CD14 expression; IRAK1 and a phosphorylated form of p38 MAPK protein. Resveratrol counteracted LPS effect... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3129991 Tue, 22 Dec 2009 00:00:00 +0100 3129991 http://www.medworm.com/index.php?rid=3129990&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20035709%26dopt%3DAbstract Authors: Mazzitelli LR, Rinaldi DE, Corradi GR, Adamo HP The plasma membrane Ca(2+) ATPase catalyzed the hydrolysis of ATP in the presence of mM concentrations of EGTA and no added Ca(2+) at a rate near 1.5 % of that attained at saturating concentrations of Ca(2+). Like the Ca-dependent ATPase, the Ca-independent activity was lower when the enzyme was autoinhibited, and increased when the enzyme was activated by acidic lipids or partial proteolysis. The ATP concentration dependence of the Ca(2+)-independent ATPase was consistent with ATP binding to the low affinity modulatory site. In this condition a small amount of hydroxylamine-sensitive phosphoenzyme was formed and rapidly decayed when chased with cold ATP. We propose that the Ca(2+)-independent ATP hydrolysis reflects the well kno... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3129990 Tue, 22 Dec 2009 00:00:00 +0100 3129990 http://www.medworm.com/index.php?rid=3119451&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20026028%26dopt%3DAbstract In this study, residues H208, Y211, R212, Q214, S215 and S216 of Mo-MLV IN were mutated to determine their role on enzyme activity. We found that Y211A, R212A, R212K and Q214A decreased integration activity, while disintegration and 3' processing were not significantly affected. By contrast H208A was completely inactive in all the assays. The core domain of Mo-MLV integrase was modeled and the flexibility of the region 207-216 was analyzed. Substitutions with low integration activity showed a lower flexibility than wild type integrase. We propose that the peptide region 207-216 is a flexible loop and that H208, Y211, R212 and Q214 of this loop are involved in the correct assembly of the DNA-integrase complex during integration. PMID: 20026028 [PubMed - as supplied by publisher] (Source... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3119451 Thu, 17 Dec 2009 00:00:00 +0100 3119451 http://www.medworm.com/index.php?rid=3119450&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20026029%26dopt%3DAbstract Authors: Hassan YI, Moriyama H, Zempleni J Holocarboxylase synthetase (HCS) catalyzes the binding of biotin to lysines in carboxylases and histones in two steps. First, HCS catalyzes the synthesis of biotinyl-5'-AMP; second, the biotinyl moiety is ligated to lysine residues. It has been proposed that step two is fairly promiscuous, and that protein biotinylation may occur in the absence of HCS as long as sufficient exogenous biotinyl-5'-AMP is provided. Here, we identified a novel polypeptide (Syn67) with a basic patch of lysines and arginines. Yeast-two-hybrid assays and limited proteolysis assays revealed that both N- and C-termini of HCS interact with Syn67. A potential target lysine in Syn67 was biotinylated by HCS only after arginine-to-glycine substitutions in Syn67 produced a hi... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3119450 Thu, 17 Dec 2009 00:00:00 +0100 3119450 http://www.medworm.com/index.php?rid=3119449&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20026030%26dopt%3DAbstract Authors: Han SN, Pang E, Zingg JM, Meydani SN, Meydani M, Azzi A Mice were supplemented with low and high doses of natural and synthetic vitamin E, T cells from the spleen isolated and stimulated with plate-bound anti-CD3 and soluble anti-CD28, and gene expression changes assessed by gene array experiments. The data obtained indicate significant qualitative and quantitative differences between the two vitamin forms in regulating gene expression in response to T cell stimulation. Marker genes have been found whose expression can be considered significant in establishing the level of, and response to vitamin E for both natural and synthetic vitamin E supplementation; unique markers for synthetic vitamin E supplementation and unique markers for natural vitamin E supplementation have been ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3119449 Thu, 17 Dec 2009 00:00:00 +0100 3119449 http://www.medworm.com/index.php?rid=3119448&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20026031%26dopt%3DAbstract Authors: Pizzuto R, Paventi G, Atlante A, Passarella S The existence of the pyruvate kinase (PK) in pig liver mitochondria was shown by monitoring photometrically the PK reaction in solubilised mitochondria with either phosphoenolpyruvate (PEP) or ADP used as a substrate. In distinction with the cytosolic isoenzyme, the mitochondrial PK showed a sigmoidal dependence on either PEP or ADP concentrations. The occurrence of the mitochondrial PK was confirmed by immunological analysis. Titration with digitonin showed that mPK is restricted to the matrix. PEP addition to mitochondria resulted in reduction of the intramitochondrial NAD(P)(+) inhibited by either the non-penetrant thiol reagent mersalyl or by arsenite, an inhibitor of the pyruvate dehydrogenase complex. Citrate/oxaloacetate app... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3119448 Thu, 17 Dec 2009 00:00:00 +0100 3119448 http://www.medworm.com/index.php?rid=3105477&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20018167%26dopt%3DAbstract Authors: Feng JJ, Cheng FC, Lin CH, Wei JW, Yang SD Some G protein-coupled receptors (GPCRs) have functional links to cancer biology, yet the manifestation of GPCRs in tumor types is little studied to date. Using a battery of radioligand binding assays, we sought to characterize GPCR recognition binding sites on HeLaS3 tumor cells. High levels of binding of the selective serotonin 5-HT(1A) receptor agonist [(3)H]8-OH-DPAT were observed in these cells. Saturation and homologous competition experiments indicated that [(3)H]8-OH-DPAT bound different populations of high and low affinity sites. In competition experiments, several serotonergic compounds displaced [(3)H]8-OH-DPAT binding with low potency from its high affinity binding sites, suggesting that low affinity binding is the predomi... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3105477 Mon, 14 Dec 2009 00:00:00 +0100 3105477 http://www.medworm.com/index.php?rid=3105476&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20018168%26dopt%3DAbstract This study determines whether mild thermotolerance (40 degrees C, 3h) can induce other defense proteins (e.g. antioxidants, anti-apoptosis proteins), and protect HeLa cells against apoptosis triggered by H(2)O(2). Protein expression and enzymatic activity of MnSOD and catalase were increased in thermotolerant cells, as well as intracellular glutathione levels and gamma-glutamylcysteine synthetase expression. Furthermore, levels of reactive oxygen species (ROS) were increased in thermotolerant cells, which caused mitochondrial membrane hyperpolarisation. Mild thermotolerance inhibited activation of the mitochondrial cascade of apoptosis by H(2)O(2). This entailed inhibition of mitochondrial Bax translocation, mitochondrial membrane depolarisation, cytochrome c release, activation of caspase... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3105476 Mon, 14 Dec 2009 00:00:00 +0100 3105476 http://www.medworm.com/index.php?rid=3105475&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20018169%26dopt%3DAbstract Authors: Kirchner T, Flemmig J, Furtmüller PG, Obinger C, Arnhold J The heme-containing enzyme myeloperoxidase (MPO) accumulates at inflammatory sites and is able to catalyse one- and two-electron oxidation reactions. Here it is shown that (-)-epicatechin, which is known to have numerous beneficial health effects, in low micromolar concentration enhances the degradation of monochlorodimedon (MCD) or the chlorination of taurine in a concentration-dependent bell-shaped manner whereas at higher concentrations it sufficiently suppresses the release of hypochlorous acid. Presented reaction mechanisms demonstrate the efficiency of micromolar concentrations of the flavan-3-ol in overcoming the accumulation of compound II that does not participate in the chlorination cycle. In case of MCD... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3105475 Mon, 14 Dec 2009 00:00:00 +0100 3105475 http://www.medworm.com/index.php?rid=3072401&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19995546%26dopt%3DAbstract Authors: Chichiarelli S, Gaucci E, Ferraro A, Grillo C, Altieri F, Cocchiola R, Arcangeli V, Turano C, Eufemi M Chromatin immunoprecipitation in M14 melanoma cells showed that the protein ERp57 (endoplasmic reticulum protein 57) binds to DNA in the proximity of STAT3 in a subset of STAT3-regulated genes. In the same cells, IL-6 induced a significant increase of the expression of one of these genes, i.e. CRP. Upon depletion of ERp57 by RNA interference, the phosphorylation of STAT3 on tyrosine 705 was decreased, and the IL-6-induced activation of CRP expression was completely suppressed. In vitro experiments showed that ERp57 is also required for the binding of STAT3 to its consensus sequence on DNA. Thus ERp57, previously shown to associate with STAT3 in the cytosol and in the nuclear ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3072401 Sat, 05 Dec 2009 00:00:00 +0100 3072401 http://www.medworm.com/index.php?rid=3072400&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19995547%26dopt%3DAbstract In this study, we investigated the mechanism of inhibition of TGF-beta signaling by the Hsp90 inhibitor geldanamycin (GA). Treatment with GA suppressed TGF-beta signaling, as evidenced by inhibition of TGF-beta-induced phosphorylation and transcriptional activity of Smad3 and decreased induction of target genes. Western blot analysis revealed that GA induced degradation of TGF-beta type I and type II receptors through a proteasome-dependent pathway. Notably, induction of Hsp70 by GA correlated with inhibition of TGF-beta signaling. Suppression of Hsp70 expression by Hsp70 siRNA or KNK437, an inhibitor of Hsp70 synthesis, blocked the inhibition of TGF-beta signaling by GA. Furthermore, Hsp70 interacted directly with TGF-beta receptors following GA treatment. Our results suggest that GA-medi... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3072400 Sat, 05 Dec 2009 00:00:00 +0100 3072400 http://www.medworm.com/index.php?rid=3072399&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19995548%26dopt%3DAbstract Authors: Gutiérrez-Aguilar M, Pérez-Martínez X, Chávez E, Uribe-Carvajal S The mitochondrial permeability transition (PT) involves the opening of a mitochondrial unselective channel (MUC) resulting in membrane depolarization and increased permeability to ions. PT has been observed in many, but not all eukaryotic species. In some species, PT has been linked to cell death, although other functions, such as matrix ion detoxification or regulation of the rate of oxygen consumption have been considered. The identification of the proteins constituting MUC would help understand the biochemistry and physiology of this channel. It has been suggested that the mitochondrial phosphate carrier is a structural component of MUC and we decided to test this in yeast mitochondria. Me... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3072399 Sat, 05 Dec 2009 00:00:00 +0100 3072399 http://www.medworm.com/index.php?rid=3072398&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19995549%26dopt%3DAbstract In this study, phenylalanines in the Abeta(1-40) sequence were substituted with tryptophan residues at either position 4 (F4W) or 19 (F19W) to probe the fibril environment. The F4W substitution did not alter self-assembly kinetics, while the F19W change slightly lengthened the lag phase without hindering fibril formation. The tryptophan fluorescence of Abeta(1-40) F19W, but not Abeta(1-40) F4W, underwent a marked blue shift during fibril formation and this shift was temporally correlated with thioflavin T binding. Isolated Abeta(1-40) F19W fibrils exhibited the largest fluorescence blue shifts consistent with W19 insertion into the Abeta(1-40) fibril inner core and direct probing of the substantially hydrophobic environment therein. PMID: 19995549 [PubMed - as supplied by publisher] (S... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3072398 Sat, 05 Dec 2009 00:00:00 +0100 3072398 http://www.medworm.com/index.php?rid=3072397&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19995550%26dopt%3DAbstract Authors: Xia S, Robertus JD The influenza A virus nonstructural protein NS1 is a multifunctional dimeric protein that acts as a potent inhibitor of the host cellular antiviral state. The C-terminal effector domain of NS1 binds host proteins, including CPSF30, and is a target for the development of new antiviral drugs. Here we present crystallographic structures of two mutant effector domains, W187Y and W187A, of influenza A/Udorn/72 virus. Unlike wild type, the mutants behave exclusively as monomers in solution based on gel filtration data and light scattering. The W187Y mutant is able to bind CPSF30 with a binding affinity close to the wild type protein; that is, it retains a receptor site for aromatic ligands nearly identical to the wild type. Therefore, this monomeric mutant protein... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3072397 Sat, 05 Dec 2009 00:00:00 +0100 3072397 http://www.medworm.com/index.php?rid=3057192&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19951695%26dopt%3DAbstract Authors: Wang Y, Becklund BR, Deluca HF The active form of vitamin D, 1alpha,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) is critical for regulation of serum calcium and phosphorus levels and for proper maintenance of bone mineralization and neuromuscular function. Biological effects of 1,25(OH)(2)D(3) are mediated through a nuclear steroid hormone receptor, known as the vitamin D receptor (VDR). The discovery of VDR in a number of different cell and tissue types, suggests that the physiological role of vitamin D may extend beyond the regulation of calcium homeostasis and bone function. Unfortunately, identification of tissues expressing VDR has been controversial due to low abundance of the receptor and quality of the antibodies used. Therefore, we elected to characterize a panel of com... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3057192 Sat, 28 Nov 2009 00:00:00 +0100 3057192 http://www.medworm.com/index.php?rid=3049016&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19944667%26dopt%3DAbstract Authors: Palfey BA, McDonald CA Flavoprotein monooxygenases reduce flavins, speed their reaction with oxygen, and stabilize a C4a-oxygen adduct long enough to use this reactive species to transfer an oxygen atom to a substrate. The flavin-oxygen adduct can be the C4a-peroxide anion, in which case it reacts as a nucleophile. The protonated adduct - the C4a-hydroperoxide - reacts as an electrophile. The elimination of H(2)O(2) competes with substrate oxygenation. This side-reaction is suppressed, preventing the waste of NAD(P)H and the production of toxic H(2)O(2). Several strategies have been uncovered that prevent the deleterious side-reaction while still allowing substrate hydroxylation. PMID: 19944667 [PubMed - as supplied by publisher] (Source: Archives of Biochemistry and Bioph... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3049016 Wed, 25 Nov 2009 00:00:00 +0100 3049016 http://www.medworm.com/index.php?rid=3049015&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19944668%26dopt%3DAbstract Authors: Kim YH, Lee C, Go H, Konishi K, Lee K, Lau PC, Yu MH We studied the decolorization of malachite green (MG) by the fungus Cunninghamella elegans. The mitochondrial activity for MG reduction was increased with a simultaneous increase of a 9-kDa protein, called CeCyt. The presence of cytochrome c in CeCyt protein was determined by optical absorbance spectroscopy with an extinction coefficient (E(550-535)) of 19.7 +/- 6.3 mM(-1) cm(-1) and reduction potential of +261 mV. When purified CeCyt was added into the mitochondria, the specific activity of CeCyt reached 440 +/- 122 mumol min(-1) mg(-1) protein. The inhibition of MG reduction by stigmatellin, but not by antimycin A, indicated a possible linkage of CeCyt activity to the Qo site of the bc1 complex. The RT-PCR results showed t... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3049015 Wed, 25 Nov 2009 00:00:00 +0100 3049015 http://www.medworm.com/index.php?rid=3049014&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19944669%26dopt%3DAbstract Authors: Battistuzzi G, Bellei M, Vlasits J, Banerjee S, Furtmüller PG, Sola M, Obinger C Eosinophil peroxidase (EPO) and lactoperoxidase (LPO) are important constituents of the innate immune system of mammals. These heme enzymes belong to the peroxidase-cyclooxygenase superfamily and catalyze the oxidation of thiocyanate, bromide and nitrite to hypothiocyanate, hypobromous acid and nitrogen dioxide that are toxic for invading pathogens. In order to gain a better understanding of the observed differences in substrate specificity and oxidation capacity in relation to heme and protein structure, a comprehensive spectroelectrochemical investigation was performed. The reduction potential (E degrees ') of the Fe(III)/Fe(II) couple of EPO and LPO was determined to be -126 mV and -176 mV... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3049014 Wed, 25 Nov 2009 00:00:00 +0100 3049014 http://www.medworm.com/index.php?rid=3049021&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19944060%26dopt%3DAbstract Authors: Oda M, Kitai A, Murakami A, Nishimura M, Ohkuri T, Abe Y, Ueda T, Nakamura H, Azuma T To evaluate the conformation of reduced HEL, the monoclonal antibodies HyC1 and HyC2, which recognize different conformational epitopes on native hen egg lysozyme (HEL), were used, and the kinetics of their interactions with native HEL, S-1,2-dicarboxyethylated HEL (DCE-HEL), and carboxymethylated Cys6 and Cys127 HEL (CM(6,127)-HEL) were assessed using surface plasmon resonance. Although their association rate constants differed 10(5)-fold, their dissociation rate constants were essentially the same, suggesting that DCE-HEL and CM(6,127)-HEL possess conformations similar to that of native HEL when they bind antibodies. We considered that the ratio of the association rate constant of reduced H... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3049021 Tue, 24 Nov 2009 00:00:00 +0100 3049021 http://www.medworm.com/index.php?rid=3049020&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19944061%26dopt%3DAbstract Authors: Kisiday JD, Vanderploeg EJ, McIlwraith CW, Grodzinsky AJ, Frisbie DD Knee osteoarthritis is accelerated by damage to the meniscus, a fibrocartilage tissue that assists in load transmission. However, little is known about the mechanical or cellular response of the meniscus to injurious overloading. Here, in vitro studies explored injury to meniscal explants using a compressive overloading protocol that has been well-characterized for articular cartilage. Cartilage samples were processed in parallel as a reference to the extensive literature on cartilage injury. Injured meniscal explants showed extensive cell death at the articulating surface but no gross tissue damage, while similar conditions of peak stress and strain resulted in cartilage surface fissures and cell death consi... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3049020 Tue, 24 Nov 2009 00:00:00 +0100 3049020 http://www.medworm.com/index.php?rid=3049019&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19944062%26dopt%3DAbstract Authors: Separovic D, Kelekar A, Nayak AK, Tarca AL, Hanada K, Pierce JS, Bielawski J The purpose of this study was to determine the sphingolipid (SL) profile in cells defective in autophagy protein ATG-7 and overall cell death after photodynamic therapy (PDT) with the photosensitizer Pc 4. MCF-7 human breast cancer cells with downregulated ATG-7 and their scrambled controls (Scr) were used. Exposure of ATG-7 knockdown cells to PDT led to increased cell killing. PDT evoked an early (2 h) greater global increase in ceramides in ATG-7 defective cells compared to Scr cells. The total increases in dihydroceramide (DHceramide) were significant at 2 h and 24 h in both cell types post-PDT. The levels of sphingosine-1-phosphate (S1P) and sphingosine were decreased below resting levels at both ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3049019 Tue, 24 Nov 2009 00:00:00 +0100 3049019 http://www.medworm.com/index.php?rid=3049018&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19944063%26dopt%3DAbstract In this study, we examined the effect of indomethacin on arachidonic acid uptake using LS174T human colon cancer cells. We here show that treatment of LS174T cells with indomethacin reduced arachidonic acid uptake as well as reduced expressions of fatty acid translocase/CD36 and peroxisome proliferators-activated receptor gamma. Since arachidonic acid is a major substrate of inflammatory mediators such as prostaglandins and leukotrienes, we believe this novel effect of indomethacin may apply to new treatment strategies that aim to suppress these mediators by decreasing the uptake of their substrates, which would eventually inhibit colorectal cancer malignancy. PMID: 19944063 [PubMed - as supplied by publisher] (Source: Archives of Biochemistry and Biophysics) Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3049018 Tue, 24 Nov 2009 00:00:00 +0100 3049018 http://www.medworm.com/index.php?rid=3049017&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19944064%26dopt%3DAbstract Authors: Talakad JC, Wilderman PR, Davydov DR, Kumar S, Halpert JR Rational mutagenesis was used to improve the thermal stability of human cytochrome P450 2B6 and canine P450 2B11. Comparison of the amino acid sequences revealed seven sites that are conserved between the stable 2B1 and 2B4 but different from those found in the less stable 2B6 and 2B11. P334S was the only mutant that showed increased heterologous expression levels and thermal stability in both 2B6 and 2B11. The mechanism of this effect was explored with pressure-perturbation spectroscopy. Compressibility of the heme pocket in variants of all four CYP2B enzymes containing proline at position 334 are characterized by lower compressibility than their more stable serine 334 counterpart. Therefore, the stabilizing effect of ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3049017 Tue, 24 Nov 2009 00:00:00 +0100 3049017 http://www.medworm.com/index.php?rid=3031427&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19932078%26dopt%3DAbstract Authors: Sun J, Druhan LJ, Zweier JL Inducible NOS (iNOS) is induced in diseases associated with inflammation and oxidative stress, and questions remain regarding its regulation. We demonstrate that reactive oxygen / nitrogen species (ROS/RNS) dose-dependently regulate iNOS function. Tetrahydrobiopterin (BH(4))-replete iNOS was exposed to increasing concentrations of ROS/RNS and activity was measured with and without subsequent BH(4) addition. Peroxynitrite (ONOO(-)) produced the greatest change in NO generation rate, approximately 95% decrease, and BH(4) only partially restored this loss of activity. Superoxide (O(2)(.-)) greatly decreased NO generation, however, BH(4) addition restored this activity. Hydroxyl radical ((.)OH) mildly decreases NO generation in a BH(4)-dependent manner.... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3031427 Thu, 19 Nov 2009 00:00:00 +0100 3031427 http://www.medworm.com/index.php?rid=3031426&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19932079%26dopt%3DAbstract Authors: Tanahashi H, Kito K, Ito T, Yoshioka K MafB is a basic leucine zipper transcription factor that plays important roles in development and differentiation processes. During osteoclastogenesis, its expression is downregulated at the transcriptional level via the JNK and p38 MAP kinase pathways. In the present study, we demonstrated that MafB protein stability is regulated by JNK and identified a phosphorylation site, Thr62. The expression of a constitutively active form of JNK (a fusion protein MKK7alpha1-JNK1beta1) promoted the degradation of MafB in COS7 cells, and a T62A substitution significantly reduced the instability of MafB. The introduction of a four-fold (T58A/T62A/S70A/S74A) substitution in an acidic transcription-activating domain almost protected the instability resu... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3031426 Thu, 19 Nov 2009 00:00:00 +0100 3031426 http://www.medworm.com/index.php?rid=3031425&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19932080%26dopt%3DAbstract Authors: Zarai Z, Bacha AB, Horchani H, Bezzine S, Zouari N, Gargouri Y, Mejdoub H A marine snail digestive phospholipase A(2) (mSDPL) was purified from delipidated hepatopancreas. Unlike known digestive phospholipases A(2), which are 14 kDa proteins, the purified mSDPL has a molecular mass of about 30 kDa. It has a specific activity of about 180 U/mg measured at 50 degrees C and pH 8.5 using phosphatidylcholine liposomes as a substrate in the presence of 4 mM NaTDC and 6 mM CaCl(2). The N-terminal amino-acid of the purified mSDPL does not share any homology with known phospholipases. Moreover, the mSDPL exhibits hemolytic activity in intact erythrocytes and can penetrate phospholipid monolayers at high surface pressure, comparable to snake venom PLA(2). These observations suggest that... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3031425 Thu, 19 Nov 2009 00:00:00 +0100 3031425 http://www.medworm.com/index.php?rid=3031424&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19932081%26dopt%3DAbstract Authors: Tang Z, Salamanca-Pinzón SG, Wu ZL, Xiao Y, Guengerich FP Human cytochrome P450 (P450) 4F11 is still considered an "orphan" because its function is not well characterized. A bacterial expression system was developed for human P450 4F11, producing approximately 230 nmol P450 from a 3-liter culture of Escherichia coli. P450 4F11 was purified and utilized for untargeted substrate searches in human liver extract using a liquid chromatography/mass spectrometry-based metabolomic and isotopic labeling approach (Z. Tang et al., Anal. Chem.81, 3071-3078, 2009). Four fatty acids-palmitic, oleic, arachidonic, and docosahexaenoic-were identified in human liver and verified as substrates of P450 4F11. The products were characterized as -hydroxylated fatty acids by gas chromatography-m... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3031424 Thu, 19 Nov 2009 00:00:00 +0100 3031424 http://www.medworm.com/index.php?rid=3031429&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19931221%26dopt%3DAbstract This study measured the zinc-binding properties of the imidase using inductively coupled plasma-atomic emission spectrometry and competition assay combined with activity determinations. Results show that each subunit of the imidase binds the zinc ion by 1:1 stoichiometry with apparent binding constant of 9.5x10(8) M(-1). The activity of the apo-imidase (20 muM) was recovered with the addition of zinc in the lower concentration (0 approximately 20 muM), whereas the enzymatic activity is decreased in the presence of high concentration of zinc (above 100 muM). The site-directed mutagenesis of His(247), His (86) or Cys(7,) Cys(108) in imidase resulted in loss of activity and zinc-binding abilities at different degrees, showing that these residues may critically affect both enzymatic activity a... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3031429 Tue, 17 Nov 2009 00:00:00 +0100 3031429 http://www.medworm.com/index.php?rid=3031428&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19931222%26dopt%3DAbstract Authors: Schlangen K, Miosic S, Halbwirth H In the petals of Dahlia variabilis, hydroxylation of chalcones at position 3 can be detected, except the well-known flavonoid 3'-hydroxylation. Although the reaction is well characterized at the enzymatic level, it remained unclear whether it is catalyzed by a flavonoid 3'-hydroxylase (F3'H, EC1.14.13.21, CYP75B) with broad substrate specificity. Two novel allelic variants of F3'H were cloned from D.variabilis, which differ only in three amino acids within their 508 residues. The corresponding recombinant enzymes show significant differences in their chalcone 3-hydroxylase (CH3H) activity. A substitution of alanine at position 425 with valine enables CH3H activity, whereas the reciprocal substitution leads to a loss of CH3H activity. Interact... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3031428 Tue, 17 Nov 2009 00:00:00 +0100 3031428 http://www.medworm.com/index.php?rid=3009008&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19919822%26dopt%3DAbstract Authors: Grellier P, Marozienė A, Nivinskas H, Sarlauskas J, Aliverti A, Cėnas N Although quinones have been the subject of great interest as possible antimalarial agents, the mechanism of their antimalarial activity is poorly understood. Flavoenzyme electrontransferase-catalyzed redox cycling of quinones, and their inhibition of the antioxidant flavoenzyme glutathione reductase (GR, EC 1.8.1.7) have been proposed as possible mechanisms. Here, we have examined the activity of a number of quinones, including the novel antitumour agent RH1, against the malaria parasite Plasmodium falciparum strain FcB1 in vitro, their single-electron reduction rates by P. falciparum ferredoxin:NADP(+) reductase (PfFNR, EC 1.18.1.2), and their ability to inhibit P. falciparum GR. The multipara... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3009008 Sat, 14 Nov 2009 00:00:00 +0100 3009008 http://www.medworm.com/index.php?rid=3009007&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19919823%26dopt%3DAbstract Authors: Nilsson T, Ivanov IV, Oliw EH CYP4F22 and CYP4F8 are expressed in epidermis, and mutations of CYP4F22 are associated with lamellar ichthyosis. Epoxyalcohols (HEETs) and epoxides (EETs) of 20:4n-6 appear to be important for the water permeability barrier of skin. Our aim was to study the MS/MS spectra and fragmentation of these compounds and to determine whether they were oxidized by CYP4F22 or CYP4F8 expressed in yeast. HEETs were prepared from 15-hydroperoxyeicosatetraenoic acid (15-HPETE), 12-HPETE, and their [(2)H(8)]labeled isotopomers, and separated by normal phase-HPLC with MS/MS analysis. CYP4F22 oxygenated 20:4n-6 at C-18, whereas metabolites of HEETs could not be identified. CYP4F8 formed 3 hydroxy metabolites of HEETs derived from 12R-HPETE with 11,12-epoxy-10-hydrox... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3009007 Sat, 14 Nov 2009 00:00:00 +0100 3009007 http://www.medworm.com/index.php?rid=3009006&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19919824%26dopt%3DAbstract Authors: Griffin MD, Dobson RC, Gerrard JA, Perugini MA Dihydrodipicolinate synthase (DHDPS, E.C. 4.2.1.52) is a tetrameric enzyme that catalyses the first committed step of the lysine biosynthetic pathway. Dimeric variants of DHDPS have impaired catalytic activity due to aberrant protein motions within the dimer unit. Thus, it is thought that the tetrameric structure functions to restrict these motions and optimise enzyme dynamics for catalysis. Despite the importance of dimer-dimer association, the interface between subunits of each dimer is small, accounting for only 4.3% of the total monomer surface area, and the structure of the interface is not conserved across species. We have probed the tolerance of dimer- dimer association to mutation by introducing amino acid substitutions wi... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3009006 Sat, 14 Nov 2009 00:00:00 +0100 3009006 http://www.medworm.com/index.php?rid=3000645&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19914197%26dopt%3DAbstract We report that this mutation renders PKCdelta apoptotically more active. Furthermore, we found that the mutant PKCdelta-S662A is tyrosine-phosphorylated and translocated to the membrane faster than its wild type counterpart. PMID: 19914197 [PubMed - as supplied by publisher] (Source: Archives of Biochemistry and Biophysics) Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3000645 Thu, 12 Nov 2009 00:00:00 +0100 3000645 http://www.medworm.com/index.php?rid=3000644&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19914198%26dopt%3DAbstract Authors: Espinoza-Fonseca LM, Wong-Ramírez C, Trujillo-Ferrara JG Plasmodium falciparum triosephosphate isomerase (PfTIM) is known to be functional only as a homodimer. Although many studies have shown that the interface Cys13 plays a major role in the stability of the dimer, a few reports have demonstrated that structurally conserved Tyr74 may be essential for the stability of PfTIM dimer. To understand the role of Tyr74, we have performed molecular dynamics (MD) simulations of monomeric and dimeric PfTIM mutated to glycine and cysteine at position 74. Simulations of the monomer revealed that mutant Tyr74Gly does not produce changes in folding and stability of the monomer. Interestingly, comparison of the flexibility of Tyr74 in the monomer and dimer revealed that this residue po... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3000644 Thu, 12 Nov 2009 00:00:00 +0100 3000644 http://www.medworm.com/index.php?rid=3000643&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19914199%26dopt%3DAbstract Authors: Gahloth D, Selvakumar P, Shee C, Kumar P, Sharma AK Earlier, the purification of a 21.4 kDa protein with trypsin inhibitory activity from seeds of Murraya koenigii has been reported. The present study, based on the amino acid sequence deduced from both cDNA and genomic DNA, establishes it to be a miraculin-like protein and provides crystal structure at 2.9 A resolution. The mature protein consists of 190 amino acid residues with seven cysteines arranged in three disulfide bridges. The amino acid sequence showed maximum homology and formed a distinct cluster with miraculin-like proteins, a soybean Kunitz super family member, in phylogenetic analyses. The major differences in sequence were observed at primary and secondary specificity sites in the reactive loop when compared to ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3000643 Thu, 12 Nov 2009 00:00:00 +0100 3000643 http://www.medworm.com/index.php?rid=3000642&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19914200%26dopt%3DAbstract Authors: Hengst JA, Guilford JM, Conroy EJ, Wang X, Yun JK Sphingosine kinase 1 (SphK1) responds to a variety of growth factor signals by increasing catalytic activity as it translocates to the plasma membrane (PM). Several studies have identified amino acids residues involved in translocation yet how SphK1 increases its catalytic activity remains to be elucidated. Herein, we report that deletion of 21 amino acids from the COOH terminus of SphK1 (1-363) results in increased catalytic activity relative to wild-type SphK1 (1-384) which is independent of the phosphorylation state of Serine 225 and PMA stimulation. Importantly, HEK293 cells stably expressing the 1-363 protein exhibit enhanced cell growth under serum-deprived cell culture conditions. Together the evidence indicates that the... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=3000642 Thu, 12 Nov 2009 00:00:00 +0100 3000642 http://www.medworm.com/index.php?rid=2985190&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19900396%26dopt%3DAbstract Authors: Bartusik D, Tomanek B The cellular monitoring of tumor response to treatments is important for drug discovery and drug development in cancer therapy. We studied efficacy of Herceptin, a common breast cancer drug conjugated with a fluorine organic compound, perfluoro-15-crown-5-ether (PFCE) which easily forms biocompatible emulsions. Three new pharmaceutical forms of Herceptin, Herceptin/PFCE, Herceptin/PFCE/Lipoplex and Herceptin/PFCE/HydraLink were synthesized for the ex vivo study of their efficacy in breast cancer treatment. The emulsions were administered to 10(9) cells.mL(-1) of HER-2 positive human adenocarcinoma (MCF-7) cells and the same amount of human mammary epithelial cells (HMEC) cultured in three dimensional (3-D) geometry using Hollow Fiber Bioreactor (HFB) devi... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2985190 Fri, 06 Nov 2009 00:00:00 +0100 2985190 http://www.medworm.com/index.php?rid=2985189&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19900397%26dopt%3DAbstract Authors: Bilbao PS, Boland R, Santillán G In the present work we studied the involvement of PKC and Src in the phosphorylation of ERK1/2, p38 and JNK1 MAPKs and in the modulation of ATF-1, c-Fos, c-Jun and JunD transcription factors by ATP in MCF-7 breast cancer cells. RT-PCR studies and nucleotide sequence analysis confirmed first the expression of P2Y(2) and P2Y(4) receptor subtypes. The use of specific inhibitors and Src antisense oligonucleotides showed that PKC, but not Src, plays a role in the phosphorylation of MAPKs by ATP. ATP stimulated the expression of c-Fos and the phosphorylation c-Jun, Jun D and ATF-1. PKC and Src only participated in c-Fos induction and in ATF-1 phosphorylation. Pharmacological inhibition of MAPKs demonstrated that c-Fos induction and phosphorylati... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2985189 Fri, 06 Nov 2009 00:00:00 +0100 2985189 http://www.medworm.com/index.php?rid=2985188&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19900398%26dopt%3DAbstract Authors: Sztolsztener ME, Strzelecka-Kiliszek A, Pikula S, Tylki-Szymanska A, Bandorowicz-Pikula J Lysosome-like storage organelles (LSOs) play a crucial role in excessive accumulation of cholesterol in the Niemann-Pick type C (NPC) disease characterized by altered vesicular traffic of lipids. Annexin A6 (AnxA6) is mainly present in cytosol but upon elevation of [Ca(2+)](in) binds to membranes. In addition, a pH or cholesterol-dependent mechanism of AnxA6 interaction with membranes was described. We found a several fold enrichment of AnxA6 in LSO compartment in fibroblasts isolated from NPC patients in comparison with fibroblasts from healthy individuals. We observed that AnxA6 relocates from cytosol to LSOs in a cholesterol-dependent manner. Cholesterol depletion caused reduction in t... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2985188 Fri, 06 Nov 2009 00:00:00 +0100 2985188 http://www.medworm.com/index.php?rid=2985187&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19900399%26dopt%3DAbstract Authors: Lemeshko VV The anticancer activity of the polycationic peptide (KLAKLAK)(2), as a possible mitochondria-damaging agent, named KLA (L-form) or kla (D-form), has been increased by the fusion with hepta-arginine cell delivery vectors r7 and R7 (peptides r7-kla and R7-KLA, respectively), as shown in the literature. We demonstrated that 3.6 muM r7-kla or R7-KLA, but not kla, caused significant permeabilization of the inner and the outer membranes of energized rat liver mitochondria. In addition, r7-kla or R7-KLA induced mitochondrial aggregation, thus causing the inhibition of metabolic activity. Potential-dependent mechanism of permeabilization of the inner mitochondrial membrane by these peptides was also observed for the plasma membrane of red blood cells. The obtained results ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2985187 Fri, 06 Nov 2009 00:00:00 +0100 2985187 http://www.medworm.com/index.php?rid=2968057&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19887064%26dopt%3DAbstract In this report we provide a kinetic assessment of hTRF1 DNA binding activity. Using intrinsic fluorescence quenching we present evidence that hTRF1 binds to both telomeric and non-telomeric DNA with kinetic discrimination to allow stable binding to telomeric tracts of DNA. The position of telomere repeats does not impact binding though the number of repeats and structure does impact binding. Kinetic analysis of DNA-dependent intrinsic tryptophan fluorescence quenching of hTRF1 revealed a two step binding process that is impacted by telomere repeat length, position, and structure. These data are consistent with existing structural and equilibrium binding data for hTRF1 recognition and binding of telomere DNA. PMID: 19887064 [PubMed - as supplied by publisher] (Source: Archives of Bioche... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2968057 Sat, 31 Oct 2009 00:00:00 +0100 2968057 http://www.medworm.com/index.php?rid=2951391&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19879854%26dopt%3DAbstract Authors: Spolitak T, Funhoff EG, Ballou DP Our previous rapid-scanning stopped-flow studies of the reaction of substrate-free cytochrome P450cam with peracids [T. Spolitak, J.H. Dawson, D.P. Ballou (2005) J. Biol. Chem. 280, 20300-20309; (2006) J. Inorg. Biochem. 100, 2034-2044; (2008) J. Biol. Inorg.Chem. 13, 599-611] spectrally characterized compound I (ferryl iron plus a porphyrin pi-cation radical (Fe(IV)=O/Por (*+))), Cpd ES, and Cpd II (Fe(IV)=O/Tyr(*) or Fe(IV)=O). We now report that reactions of CYP153A6 with peracids yield all these intermediates, with kinetic profiles allowing better resolution of all forms at pH 8.0 compared to similar reactions with WT P450cam. Properties of the reactions of these higher oxidation state intermediates were determined in double mixing experim... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2951391 Thu, 29 Oct 2009 00:00:00 +0100 2951391 http://www.medworm.com/index.php?rid=2951390&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19879855%26dopt%3DAbstract Authors: Sell DR, Nemet I, Monnier VM Collagen-linked fluorescence at excitation/emission 370/440 nm has widely been used as a marker for advanced glycation in studies of aging, diabetic complications and end-stage renal disease (ESRD). Diagnostic devices measuring skin autofluorescence at this wavelength revealed an association between fluorescence and cardiovascular morbidity and mortality. We now report the presence of a major fluorophore (LW-1) in human skin collagen which increases with age, diabetes and ESRD. It has a molecular weight of 623.2 Da, a UV maximum at 348 nm, and involves a lysine residue in an aromatic ring. LW-1 could not be synthesized using traditional glycation chemistry suggesting a complex mechanism of formation, perhaps related to hypoxia since elevated levels... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2951390 Thu, 29 Oct 2009 00:00:00 +0100 2951390 http://www.medworm.com/index.php?rid=2935346&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19857456%26dopt%3DAbstract Authors: Jang HH, Kim DH, Ahn T, Yun CH We investigated the interaction of human P450 1B1 (CYP1B1) with various phospholipid bilayers using the N-terminally deleted (Delta2-4)CYP1B1 and (Delta2-26)CYP1B1 enzymes. Among anionic phospholipids, phosphatidic acid (PA) and cardiolipin specifically increased the catalytic activities, membrane binding affinities, and thermal stabilities of both CYP1B1 proteins when phosphatidylcholine matrix was gradually replaced with these anionic phospholipids. PA- or cardiolipin- dependent changes of CYP1B1 conformation were revealed by altered Trp fluorescence and CD spectra. However, both PA and cardiolipin exerted more significant effects with the (Delta2-4)CYP1B1 than the (Delta2-26)CYP1B1 implying the functional importance of N-terminal region for th... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2935346 Fri, 23 Oct 2009 00:00:00 +0100 2935346 http://www.medworm.com/index.php?rid=2935347&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19854152%26dopt%3DAbstract Authors: Lu Q, McAlister-Henn L Yeast peroxisomal NADP(+)-specific isocitrate dehydrogenase (IDP3) contains a canonical type I peroxisomal targeting sequence (a carboxyl-terminal Cys-Lys-Leu tripeptide), and provides the NADPH required for beta-oxidation of some fatty acids in that organelle. Cytosolic yeast IDP2 carrying a PTS1 (IDP2(+CKL)) was only partially localized to peroxisomes, and the enzyme was able to function in lieu of either peroxisomal IDP3 or cytosolic IDP2. The analogous isocitrate dehydrogenase enzyme (IDPA) from Aspergillus nidulans, irrespective of the presence or absence of a putative PTS1, was found to exhibit patterns of dual compartmental distribution and of dual function in yeast similar to those observed for IDP2(+CKL). To test a potential cellular limit on pe... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2935347 Thu, 22 Oct 2009 00:00:00 +0100 2935347 http://www.medworm.com/index.php?rid=2935350&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19853572%26dopt%3DAbstract Authors: Parua PK, Mondal A, Parrack P The CII protein of bacteriophage lambda is the key regulator for the lytic-lysogenic choice of the viral lifecycle. An unstable homotetrameric transcription activator of the three phage promoters p(E), p(I) and p(aQ), lambda CII is stabilized by lambdaCIII and destabilized by the host protease, E. coli HflB (FtsH). In addition, other E. coli proteins HflK, HflC and HflD also influence lysogeny by acting upon CII. Among these, HflD (22.9 kDa), a peripheral membrane protein that is exposed towards the cytoplasm, interacts with CII and decreases the frequency of lysogenization of lambda by stimulating the degradation of CII. In the present study we show that in addition to helping CII degradation, HflD inhibits the DNA binding by CII, thereby inhibit... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2935350 Wed, 21 Oct 2009 00:00:00 +0100 2935350 http://www.medworm.com/index.php?rid=2935349&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19853573%26dopt%3DAbstract Authors: Batista IF, Ramos OH, Ventura JS, Junqueira-de-Azevedo IL, Ho PL, Chudzinski-Tavassi AM Bioactive compounds of great interest are found in the saliva of hematophagous organisms. While exploring a cDNA library derived from the salivary glands of the tick Amblyommacajennense, a transcript that codes for a protein with unique structure (containing an N-terminal Kunitz-type domain and a C-terminus with no homology to any annotated sequences) was found. The recombinant mature form of this protein ( approximately 13.5 kDa) was produced in E. coli BL21 (DE3), and it was able to inhibit Factor Xa (FXa) and extend global blood clotting times in vitro and ex vivo. Static and dynamic predictions of its tertiary structure indicate regions that may be related to its FXa inhibitor function.... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2935349 Wed, 21 Oct 2009 00:00:00 +0100 2935349 http://www.medworm.com/index.php?rid=2935348&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19853574%26dopt%3DAbstract Authors: Cardinali B, Profumo A, Aprile A, Byron O, Morris G, Harding SE, Stafford WF, Rocco M The shape and solution properties of fibrinogen are affected by the location of the C-terminal portion of the Aalpha chains, which is presently still controversial. We have measured the hydrodynamic properties of a human fibrinogen fraction with these appendages mostly intact, of chicken fibrinogen, where they lack eleven characteristic thirteen-amino acids repeats, and of human fragment X, a plasmin early degradation product in which they have been removed. The human fibrinogen/fragmentX samples were extensively characterized by SDS-PAGE/Western blotting and mass spectrometry, allowing their composition to be precisely determined. The solution properties of all samples were then investigated... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2935348 Wed, 21 Oct 2009 00:00:00 +0100 2935348 http://www.medworm.com/index.php?rid=2924016&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19850002%26dopt%3DAbstract Authors: Mowat CG, Gazur B, Campbell LP, Chapman SK There are many examples of oxidative enzymes containing both flavin and heme prosthetic groups that carry out the oxidation of their substrate. For the purpose of this article we have chosen five systems. Two of these, the L-lactate dehydrogenase flavocytochrome b(2) and cellobiose dehydrogenase, carry out the catalytic chemistry at the flavin group. In contrast, the remaining three require activation of dioxygen at the heme group in order to accomplish substrate oxidation, these being flavohemoglobin, a nitric oxide dioxygenase, and the monooxygenases nitric oxide synthase and flavocytochrome P450 BM3, which functions as a fatty acid hydroxylase. In the light of recent advances we will describe the structures of these enzymes, some o... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2924016 Mon, 19 Oct 2009 00:00:00 +0100 2924016 http://www.medworm.com/index.php?rid=2924015&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19850003%26dopt%3DAbstract Authors: Landrum JT, Chatfield DC, Mebel AA, Alvarez-Calderon F, Fernandez MV Conformation affects a carotenoid's ability to bind selectively to proteins. We calculated adiabatic energy profiles for rotating the ring end-groups around the C6-C7 bond and for flexing of the ring with respect to the polyene chain. The choice of computational methods is important. A low, 4.2 kcal/mol barrier to rotation exists for a beta-ring. An 8.3 kcal/mol barrier exists for rotation of an epsilon-ring. Rotation of the epsilon-ring is sensitive to substitution at C3. In the absence of external forces neither beta- nor epsilon- rings are rotationally constrained. The nearly parallel alignment of the beta-ring to the C6-C7 bond axis contrasts to the more perpendicular orientation of the epsilon-ring. Flex... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2924015 Mon, 19 Oct 2009 00:00:00 +0100 2924015 http://www.medworm.com/index.php?rid=2924014&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19850004%26dopt%3DAbstract Authors: Suquet C, Warren JJ, Seth N, Hurst JK The prospects for using bacterial DNA as an intrinsic probe for HOCl and secondary oxidants/chlorinating agents associated with it has been evaluated using both in vitro and in vivo studies. Single-strand and double-strand breaks occurred in bare plasmid DNA that had been exposed to high levels of HOCl, although these reactions were very inefficient compared to polynucleotide chain cleavage caused by the OH(*)-generating reagent, peroxynitrite. Plasmid nicking was not increased when intact Escherichia coli were exposed to HOCl; rather, the amount of recoverable plasmid diminished in a dose-dependent manner. At concentration levels of HOCl exceeding lethal doses, genomic bacterial DNA underwent extensive fragmentation and the amount of prec... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2924014 Mon, 19 Oct 2009 00:00:00 +0100 2924014 http://www.medworm.com/index.php?rid=2909829&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19836342%26dopt%3DAbstract Authors: Braker JD, Hodel KJ, Mullins DR, Friesen JA CTP:phosphocholine cytidylyltransferase (CCT), critical for phosphatidylcholine biosynthesis, is activated by translocation to the membrane surface. The lipid activation region of Caenorhabditis elegans CCT is between residues 246 and 266 of the 347 amino acid polypeptide, a region proposed to form an amphipathic alpha helix. When leucine 246, tryptophan 249, isoleucine 256, isoleucine 257, or phenylalanine 260, on the hydrophobic face of the helix, were changed individually to serine low activity was observed in the absence of lipid vesicles, similar to wild-type CCT, while lipid stimulated activity was reduced compared to wild-type CCT. Mutational analysis of phenylalanine 260 implicated this residue as a contributor to auto-inhibi... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2909829 Tue, 13 Oct 2009 23:00:00 +0100 2909829 http://www.medworm.com/index.php?rid=2895248&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19822127%26dopt%3DAbstract Authors: Spencer JP, Vauzour D, Rendeiro C Evidence suggests that a group of phytochemicals known as flavonoids are highly effective in reversing age-related declines in neuro-cognitive performance through their ability to interact with the cellular and molecular architecture of the brain responsible for memory and by reducing neuronal loss due to neurodegenerative processes. In particular, they may increase the number of, and strength of, connections between neurons, via their specific interactions with the ERK and Akt pathways, leading to an increase in neurotrophins such as BDNF. Concurrently, their effects on the peripheral and cerebral vascular system may also lead to enhancements in cognitive performance through increased brain blood flow and an the ability to initiate neurogenes... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2895248 Thu, 08 Oct 2009 23:00:00 +0100 2895248 http://www.medworm.com/index.php?rid=2887315&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19819219%26dopt%3DAbstract Authors: Pettigrew DW Unlike those for monomeric superfamily members, heterotropic allosteric effectors of the tetrameric E. coli glycerol kinase (EGK) bind to only one of the two domains that define the catalytic cleft and far from the active site. An R369A amino acid substitution removes oligomeric interactions of a novel mini domain-swap loop of one subunit with the catalytic site of another subunit, and an A65T substitution perturbs oligomeric interactions in a second interface. Linked-functions enzyme kinetics, analytical ultracentrifugation, and FRET are used to assess effects of these substitutions on the allosteric control of catalysis. Inhibition by phosphotransferase system protein IIA(Glc) is reduced by the R369A substitution, and inhibition by fructose 1,6-bisphosphate is a... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2887315 Wed, 07 Oct 2009 23:00:00 +0100 2887315 http://www.medworm.com/index.php?rid=2887316&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19818729%26dopt%3DAbstract Authors: Lugo MR, Sharom FJ P-Glycoprotein (ABCB1) is an ATP-driven efflux pump which binds drugs within a large flexible binding pocket. Intrinsic Trp fluorescence was used to probe the interactions of LDS-751 (2-[4-(4-[dimethylamino]phenyl)-1,3-butadienyl]-3-ethylbenzo-thiazolium perchlorate) with purified P-glycoprotein, using steady-state/lifetime measurements and collisional quenching. The fast decay component of P-glycoprotein intrinsic fluorescence (tau(1) = 0.97 ns) was unaffected by LDS-751 binding, while the slow decay component (tau(2) = 4.02 ns) was quenched by dynamic and static mechanisms. Both the wavelength dependence of the decay kinetics, and the time-resolved emission spectra, suggested the existence of excited-state relaxation processes within the protein matrix on ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2887316 Tue, 06 Oct 2009 23:00:00 +0100 2887316 http://www.medworm.com/index.php?rid=2870657&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19810214%26dopt%3DAbstract Authors: Lal N, Kumar J, Erdahl WE, Pfeiffer DR, Gadd ME, Graff G, Yanni JM We investigated the effects of several non-steroidal anti-inflammatory drugs on swelling related properties of mitochondria, with an emphasis on compounds that are marketed and utilized topically in the eye (nepafenac, ketorolac, diclofenac, bromfenac), and compared these to the effects of amfenac (a metabolite of nepafenac) and to celecoxib (active principle of Celebrex). With the exception of the last compound, none of the drugs promote swelling of normal mitochondria that are well energized by succinate oxidation. However, swelling is seen when the mitochondria are under an oxidative stress due to the presence of t-butylhydroperoxide. When used at 200 microM the order of potency is celecoxib > bromfenac &... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2870657 Wed, 30 Sep 2009 23:00:00 +0100 2870657 http://www.medworm.com/index.php?rid=2863233&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19800306%26dopt%3DAbstract Authors: Zhu XM, Yao YM, Liang HP, Liu F, Dong N, Yu Y, Sheng ZY The present study was performed to clarify the effects of high mobility group box-1 protein (HMGB1), a recently described late-acting pro-inflammatory cytokine, on apoptosis of macrophages. Treatment with HMGB1 (0.01, 0.1, 1, 10 mug/ml for 24 hours, or 10 mug/ml for 6, 12, 24, 48 hours) resulted in a dose- and time- dependent induction of apoptosis in mice macrophages, peaked at 24 hours after 10 mug/ml HMGB1 stimulation. HMGB1 treatment enhanced the receptor for advanced glycation endproducts (RAGE) expression and caspase-3 activation in macrophages. Blockage of RAGE and caspase-3 activation could significantly reduce apoptosis of macrophages induced by HMGB1. The activity of NF-kappaB/p65 in macrophages was decreased af... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2863233 Tue, 29 Sep 2009 23:00:00 +0100 2863233 http://www.medworm.com/index.php?rid=2863232&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19800307%26dopt%3DAbstract Authors: Campo GM, Avenoso A, Campo S, Traina P, D'Ascola A, Calatroni A Lipopolysaccharide (LPS)-mediated activation of toll-like receptor-4 (TLR-4) complex induces specific signalling pathways, such as the myeloid differentiation primary response protein-88 (MyD88) and the tumor necrosis factor receptor-associated factor-6 (TRAF6), involving NF-kB activation. As previous data reported that hyaluronan (HA) and heparan sulphate (HS) may interact with TLR-4, the aim of this study was to investigate whether glycosaminoglycans (GAGs) may modulate the TLR-4 receptor in a model of LPS-induced inflammatory cytokines in mouse chondrocytes. LPS stimulation up-regulated all inflammation parameters. The GAG treatment produced various effects: HA reduced MyD88 and TRAF6 levels and NF-kB activatio... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2863232 Tue, 29 Sep 2009 23:00:00 +0100 2863232 http://www.medworm.com/index.php?rid=2863231&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19800308%26dopt%3DAbstract Authors: Galaleldeen A, Strange R, Whitson LJ, Antonyuk S, Narayana N, Taylor AB, Schuermann JP, Holloway SP, Hasnain SS, Hart PJ Amyotrophic lateral sclerosis (ALS) is a fatal, progressive neurodegenerative disease characterized by the destruction of motor neurons in the spinal cord and brain. A subset of ALS cases are linked to dominant mutations in copper-zinc superoxide dismutase (SOD1). The pathogenic SOD1 variants A4V and G93A have been the foci of multiple studies aimed at understanding the molecular basis for SOD1-linked ALS. The A4V variant is responsible for the majority of familial ALS cases in North America, causing rapidly progressing paralysis once symptoms begin and the G93A SOD1 variant is overexpressed in often studied murine models of the disease. Here we report the t... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2863231 Tue, 29 Sep 2009 23:00:00 +0100 2863231 http://www.medworm.com/index.php?rid=2863230&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19800309%26dopt%3DAbstract Authors: Reinau ME, Otzen DE The cytosolic protein Ffh transports membrane proteins from the ribosome to the inner membrane in complex with 4.5S RNA. Here we show that native Ffh binds to the hydrophobic probe ANS in a 1 Ffh:3 ANS stoichiometry, revealing a hydrophobic binding site. Thermal precipitation of Ffh is shifted upwards by approximately 10 degrees C by ANS or substrate protein, suggesting that the hydrophobic binding site makes the protein aggregation prone. Chemical denaturation confirm that Ffh is a rather unstable protein. 4.5S RNA destabilizes Ffh further, suggesting it keeps the protein in a more open conformation than the apoprotein. E. coli lipid and DOPG (and to a smaller extent DOPC) increases Ffh's alpha-helical content, possibly related to Ffh's role in guiding mem... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2863230 Tue, 29 Sep 2009 23:00:00 +0100 2863230 http://www.medworm.com/index.php?rid=2863229&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19800310%26dopt%3DAbstract Authors: Anand P, Kwak Y, Simha R, Donaldson RP Peroxisomes contain oxidases that produce H(2)O(2), which can result in protein oxidation. To test the vulnerability of peroxisomal proteins to oxidation in vivo the organelles were isolated from castor bean endosperm incubated with H(2)O(2). When peroxisomes were exposed to H(2)O(2)in vivo, the peroxisomal proteins exhibited an increase in carbonylation as detected in avidin blots of biotin hydrazide derivitized samples. Biotin tagged peptides from trypsin digests of the proteins were analyzed by mass spectroscopy and compared to the masses of peptides from the same protein that had not been biotin tagged and from proteins not exposed to excess H(2)O(2). H(2)O(2) exposure was found to increase the activity of catalase (CAT), and to incre... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2863229 Tue, 29 Sep 2009 23:00:00 +0100 2863229 http://www.medworm.com/index.php?rid=2863234&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19799852%26dopt%3DAbstract In this study, we attempted to establish a new method to evaluate gluconeogenesis using rat H4IIE hepatoma cells. High-density preculture and exposure to hypertonic solutions, which are known to upregulate the expression of gluconeogenic genes, enhanced glucose release (GR) promoted by gluconeogenic substrates (GS: 1 mM pyruvate and 10 mM lactate). Our method was also applicable to the human hepatoma HepG2 cells. Measurement of glycogen content in HepG2 cells revealed that GR was compensated by glycogenolysis in the basal state and was generated by gluconeogenesis in the presence of GS. The optimized conditions increased the expression of gluconeogenic genes in HepG2 cells. Insulin and metformin dose-dependently inhibited GR and 8-(4-chlorophenylthio)-cAMP (CPT-cAMP) increased it. These re... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2863234 Mon, 28 Sep 2009 23:00:00 +0100 2863234 http://www.medworm.com/index.php?rid=2858550&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19796626%26dopt%3DAbstract Authors: Vikhoreva NN, Vikhorev PG, Fedorova MA, Hoffmann R, Månsson A, Kuleva NV One important aspect of oxidative stress is chemical modification of lipids, proteins and nucleic acids. Copper has been shown to be one of the agents causing oxidative stress. In muscles copper binds to Cys 374 of the actin monomer and catalyzes interchain S-S bond formation in F-actin. The aim of the present work was to study the functional consequences of actin modifications, induced by copper treatment of Mytilus edulis in vivo, on the in vitro motility parameters of isolated actin filaments from foot and adductor muscles. CuCl(2) treatment reduced the sliding velocity of actin filaments extracted from foot muscle by about 22% and increased their flexibility by 1.7 times, while had no effect on t... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2858550 Sun, 27 Sep 2009 23:00:00 +0100 2858550 http://www.medworm.com/index.php?rid=2847160&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19782042%26dopt%3DAbstract In this report, using multiple biochemical and subcellular fractionation techniques we demonstrate that endogenous SphK1 protein and its substrate, D-erythro sphingosine, are present within the PMLRM. Additionally, we demonstrate that the PMA stimulation of SphK1 localized to the PMLRM results in production of sphingosine-1-phosphate as well as induction of cell growth under serum-deprivation conditions. We further report that Ser225Ala and Thr54Cys mutations, reported to abrogate phosphatidylserine binding, block SphK1 targeting to the PMLRM and SphK1 induced cell growth. Together these findings provide direct evidence that the PMLRM is the major site-of-action for SphK1 to overcome serum-deprived cell growth inhibition. PMID: 19782042 [PubMed - as supplied by publisher] (Source: Arch... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2847160 Tue, 22 Sep 2009 23:00:00 +0100 2847160 http://www.medworm.com/index.php?rid=2829134&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19772851%26dopt%3DAbstract In this report, we expand on our earlier study and demonstrate that P-gp1 expression in drug resistant cells modulates collateral sensitivity. Using P-gp1-specific siRNA, P-gp1 expression in the multidrug resistant CH(R)C5 cells was significantly down-regulated beginning on day 2 post-transfection of siRNA. Furthermore, down-regulation of P-gp1 led to increased sensitivity of CH(R)C5 cells to paclitaxel and doxorubicin, but not to cis-platinum, due to inhibition of P-gp1 drug efflux pump. Down regulation of P-gp1 expression completely reversed collateral sensitivity to verapamil and two other drugs, progesterone and deoxycorticosterone. Moreover, known inhibitors of ETC, rotenone and antimycin A which cause an increase in reactive oxygen species, synergized with verapamil-induced collatera... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2829134 Fri, 18 Sep 2009 23:00:00 +0100 2829134 http://www.medworm.com/index.php?rid=2829133&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19772852%26dopt%3DAbstract Authors: Gargouri M, Gallois B, Chaudière J Anthocyanidin reductase from Vitis vinifera catalyzes an NADPH-dependent double reduction of anthocyanidins. At pH 7.5 and 30 degrees C, steady-state kinetics support a hyperbolic and rapid-equilibrium ordered mechanism, with NADPH binding first, K(M(cyan)) = 2.82 +/- 0.66 muM and K(i(NADPH)) = 111 +/- 23 muM. The chromatographic method of Hummel and Dreyer was used for binding-equilibrium studies of NADPH, NADP(+) and catechin, at pH 7. This confirmed hyperbolic binding of NADPH and NADP(+) to the free enzyme, with a single binding site each and with dissociation constants K(NADPH) = 45.9 +/- 2 muM and K(NADP)+ = 83 +/- 5 muM. There was no significant binding of catechin. We conclude i) that the most likely mechanism is sequential order... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2829133 Fri, 18 Sep 2009 23:00:00 +0100 2829133 http://www.medworm.com/index.php?rid=2829132&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19772853%26dopt%3DAbstract Authors: Potrykus J, Flemming J, Bearne SL Cofactor-independent glutamate racemases (GRs) that supply the d-glutamate required for biosynthesis of the peptidoglycan that encapsulates bacterial cells are attractive targets for the development of antibacterial drugs. Recombinant GR from Fusobacterium nucleatum (FnGR), a Gram-negative anaerobe involved in periodontal disease, was overproduced, purified, and characterized. Unlike most other GRs, FnGR is a pseudosymmetric enzyme, catalyzing the racemization of glutamate enantiomers with similar kinetic parameters (k(cat)(l-->d) = 17.4+/-0.8 s(-1), K(m)(l-->d) = 1.04+/-0.07 mM, k(cat)(d-->l) = 26+/-1 s(-1), and K(m)(d-->l) = 1.7+/-0.1 mM; pH optimum approximately 8.5). Mutational analysis of residue 151 (A151V) located at the ent... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2829132 Fri, 18 Sep 2009 23:00:00 +0100 2829132 http://www.medworm.com/index.php?rid=2829131&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19772854%26dopt%3DAbstract In conclusion, this study demonstrates the important role of mitochondrial biogenesis dysfunction in TG-induced lipotoxicity in macrophages. PMID: 19772854 [PubMed - as supplied by publisher] (Source: Archives of Biochemistry and Biophysics) Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2829131 Fri, 18 Sep 2009 23:00:00 +0100 2829131 http://www.medworm.com/index.php?rid=2829130&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19772855%26dopt%3DAbstract Authors: Lai H, Feng M, Roxas-Duncan V, Dakshanamurthy S, Smith LA, Yang DC Quinolinol derivatives were found to be effective inhibitors of botulinum neurotoxin serotype A (BoNT/A). Studies of the inhibition and binding of 7-(phenyl(8-quinolinylamino)methyl)-8-quinolinol (QAQ) to the light chain domain (BoNT/A LC) showed that QAQ is a non-competitive inhibitor for the zinc protease activity. Binding and molecular modeling studies reavel that QAQ binds to a hydrophobic pocket near the active site. Its inhibitor effect does not involve the removal of zinc ion from the light chain. A 24-mer SNAP-25 peptide containing E183 to G206 with Q197C mutation (Peptide C) binds to BoNT/A LC with an unusually slow second order binding rate constant of 76.7 M(-1)s(-1). QAQ binds to Zn(2+)-free BoNT/A ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2829130 Fri, 18 Sep 2009 23:00:00 +0100 2829130 http://www.medworm.com/index.php?rid=2822361&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19769937%26dopt%3DAbstract Authors: Kumar R Osmolytes are typically accumulated in the intracellular environment at relatively high concentrations when cells/tissues are subjected to stress conditions. Osmolytes are common in a variety of organisms, including microorganisms, plants, and animals. They enhance thermodynamic stability of proteins by providing natively-folded conformations without perturbing other cellular processes. By burying the backbone into the core of folded proteins, osmolytes can provide significant stability to proteins. Two properties of osmolytes are particularly important: i) their ability to impart increased thermodynamic stability to folded proteins; and ii) their compatibility in the intracellular environment at high concentrations. Under physiological conditions, the cellular composi... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2822361 Thu, 17 Sep 2009 23:00:00 +0100 2822361 http://www.medworm.com/index.php?rid=2822364&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19766586%26dopt%3DAbstract In this report, we demonstrate that an early critical autolytic event, we have termed pre-processing, is accelerated at acidic pH (pH 5.5) while autolytic activation is abrogated under the same conditions. Likewise, we found that pre-processing is hindered and autolytic activation is facilitated in neutral pH conditions, and thus demonstrates a pH-dependent shift in substrate selectivity. This finding is further supported by two peptide substrates corresponding to the pre-processing and C-terminal scissile bonds that were preferentially cleaved at acidic and neutral pH, respectively. Lastly, we found fibronectin cleavage to be attenuated at pH 5.5, while two novel substrates, brevican, and vitronectin, were readily cleaved in neutral or acidic conditions. PMID: 19766586 [PubMed - as su... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2822364 Wed, 16 Sep 2009 23:00:00 +0100 2822364 http://www.medworm.com/index.php?rid=2822363&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19766587%26dopt%3DAbstract Authors: Muñoz-Clares RA, Díaz-Sánchez AG, González-Segura L, Montiel C The betaine aldehyde dehydrogenases (BADH; E.C. 1.2.1.8) are so called because they catalyze the irreversible NAD(P)(+)-dependent oxidation of betaine aldehyde to glycine betaine, which may function as (i) a very efficient osmoprotectant accumulated by both prokaryotic and eukaryotic organisms to cope with osmotic stress, (ii) a metabolic intermediate in the catabolism of choline in some bacteria such as the pathogen Pseudomonas aeruginosa, or (iii) a methyl donor for methionine synthesis. BADH enzymes can also use as substrates aminoaldehydes as well as other quaternary ammonium and tertiary sulfonium compounds, thus participating in polyamine catabolism and in the synthesis of gamma-aminobutyr... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2822363 Wed, 16 Sep 2009 23:00:00 +0100 2822363 http://www.medworm.com/index.php?rid=2822362&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19766588%26dopt%3DAbstract Authors: Kuntothom T, Luang S, Harvey AJ, Fincher GB, Opassiri R, Hrmova M, Cairns JR Plant beta-d-mannosidases and a rice beta-d-glucosidase, Os3BGlu7, with weak beta-d-mannosidase activity, cluster together in phylogenetic analysis. To investigate the relationship between substrate specificity and amino acid sequence similarity in family GH1 glycoside hydrolases, Os3BGlu8 and Os7BGlu26, putative rice beta-d-glucosidases from this cluster, and a beta-d-mannosidase from barley (rHvBII), were expressed in Escherichia coli and characterized. Os3BGlu8, the amino acid sequence and molecular model of which are most similar to Os3BGlu7, hydrolysed 4-nitrophenyl- beta-d-glucopyranoside (4NPGlc) faster than 4-nitrophenyl- beta-d-mannopyranoside (4NPMan), while Os7BGlu26, which is most similar ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2822362 Wed, 16 Sep 2009 23:00:00 +0100 2822362 http://www.medworm.com/index.php?rid=2804795&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19755112%26dopt%3DAbstract Authors: Whittaker MM, Whittaker JW Metal uptake by the antioxidant defense metalloenzyme manganese superoxide dismutase (MnSOD) is an essential step in the functional maturation of the protein that is just beginning to be investigated in detail. We have extended earlier in vitro studies on metal binding by the dimeric Escherichia coli apo-MnSOD to investigate the mechanism of metal uptake by tetrameric human and Thermus thermophilus apo-MnSODs. Like the E. coli apo-MnSOD, these proteins also bind metal ions in vitro in a thermally-activated, pH-sensitive process. However, metal uptake by the tetrameric apo-MnSODs exhibits a number of important differences. In particular, there is no indication of conformational gating requirement for metal binding for these proteins, and the reaction ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2804795 Fri, 11 Sep 2009 23:00:00 +0100 2804795 http://www.medworm.com/index.php?rid=2782435&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19735641%26dopt%3DAbstract Authors: Linard D, Kandlbinder A, Degand H, Morsomme P, Dietz KJ, Knoops B Mitochondria are metabolically highly active cell organelles that are also implicated in reactive oxygen species production and in cell death regulation. Cyclophilin D, the only human mitochondrial isoform of cyclophilins, plays an essential role in the formation of the mitochondrial permeability transition pore leading to cell necrosis. Recently, it has been shown that redox environment modifies structural and functional properties of some plant cyclophilins. Here, it is shown that oxidation of human cyclophilin D influences the conformation of the enzyme but also its activity. Site-directed mutagenized variants of cyclophilin D allowed the identification of cysteine 203 as an important redox-sensitive residue.... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2782435 Thu, 03 Sep 2009 23:00:00 +0100 2782435 http://www.medworm.com/index.php?rid=2775162&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19733546%26dopt%3DAbstract Authors: Lee SJ, Kim SK, Kim WJ, Moon SK Cordycepin (3'-deoxyadenosine), a bioactive compound of Cordyceps militaris, has many pharmacological activities. The present study reveals novel molecular mechanisms for the anti-tumor effects of cordycepin in two different bladder cancer cell lines, 5637 and T-24 cells. Cordycepin treatment, at a dose of 200 M (IC(50)) during cell cycle progression resulted in significant and dose-dependent growth-inhibition, which was largely due to G2/M phase arrest, and resulted in an up-regulation of p21WAF1 expression, independent of the p53 pathway. Moreover, treatment with cordycepin induced phosphorylation of JNK (c-Jun N-terminal kinases). Blockade of JNK function using SP6001259 (JNK-specific inhibitor) and small interfering RNA (si-JNK1) rescued cor... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2775162 Wed, 02 Sep 2009 23:00:00 +0100 2775162 http://www.medworm.com/index.php?rid=2775163&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19733148%26dopt%3DAbstract This study demonstrates the susceptibility of CBS to reactive oxygen/nitrogen species, with potential relevance to hyperhomocysteinemia, a risk factor for cardiovascular diseases. PMID: 19733148 [PubMed - as supplied by publisher] (Source: Archives of Biochemistry and Biophysics) Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2775163 Tue, 01 Sep 2009 23:00:00 +0100 2775163 http://www.medworm.com/index.php?rid=2770477&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19728984%26dopt%3DAbstract Authors: Kulmacz RJ, Tsai AL The cyclooxygenase and peroxidase activities of prostaglandin H synthase (PGHS)-1 and -2 have complex kinetics, with the cyclooxygenase exhibiting feedback activation by product peroxide and irreversible self-inactivation, and the peroxidase undergoing an independent self-inactivation process. The mechanistic bases for these complex, non-linear steady-state kinetics have been gradually elucidated by a combination of structure/function, spectroscopic and transient kinetic analyses. It is now apparent that most aspects of PGHS-1 and -2 catalysis can be accounted for by a branched chain mechanism involving a classic heme-based peroxidase cycle and a radical-based cyclooxygenase cycle. The two cycles are linked by the Tyr385 radical, which originates from an ox... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2770477 Sun, 30 Aug 2009 23:00:00 +0100 2770477 http://www.medworm.com/index.php?rid=2770476&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19728985%26dopt%3DAbstract In this study, we have rationally designed and analyzed the catalytic and self-assembly properties of several trans-DSL ribozymes with different sets of natural and artificial GNRA-receptor clamps. Two variants newly designed in this study showed significantly enhanced catalytic properties with respect of the original trans-DSL construct. While this work allows dissection of the turnover and catalytic properties of the trans-DSL ribozyme, it also emphasizes the remarkable modularity of RNA tertiary structure for nano-construction of complex functions. PMID: 19728985 [PubMed - as supplied by publisher] (Source: Archives of Biochemistry and Biophysics) Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2770476 Sun, 30 Aug 2009 23:00:00 +0100 2770476 http://www.medworm.com/index.php?rid=2770475&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19728986%26dopt%3DAbstract Authors: Chaiyen P 2-methyl-3-hydroxypyridine-5-carboxylic acid (MHPC) oxygenase (MHPCO) and 5-pyridoxic acid oxygenase are flavoenzymes catalyzing an aromatic hydroxylation and a ring-cleavage reaction. Both enzymes are involved in biodegradation of vitamin B6 in bacteria. Oxygen-tracer experiments have shown that the enzymes are monooxygnases since only one atom of molecular oxygen is incorporated into the products. Kinetics of MHPCO has shown that the enzyme is similar to single-component flavoprotein hydroxylases in that the binding of MHPC is required prior to the flavin reduction by NADH, and C4a-hydroperoxy-FAD and C4a-hydroxy-FAD are found as intermediates. Investigation on the protonation status of the substrate upon binding to the enzyme has shown that only the tri-ionic form... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2770475 Sun, 30 Aug 2009 23:00:00 +0100 2770475 http://www.medworm.com/index.php?rid=2758929&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19723500%26dopt%3DAbstract In this study, we characterized the denaturant-induced unfolding of synaptotagmin 1, C2A domain in a residue-specific manner by NMR spectroscopy. The amide protons of 30 residues distributed throughout the 3D structure of the whole protein could be followed in a series of (1)H-(15)N HSQC spectra recorded from 0 to 8 M urea under equilibrium conditions. The midpoint for the urea-induced unfolding obtained from NMR coincides with those obtained from steady state fluorescence and CD spectroscopy, revealing that the protein unfolds via a two-state mechanism without accumulating stable intermediates. The thermodynamic parameter obtained from the denaturation curve illustrates the cooperative unfolding of the C2A domain. The implications of C2A domain folding in relation to the release of FGF-1 ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2758929 Fri, 28 Aug 2009 23:00:00 +0100 2758929 http://www.medworm.com/index.php?rid=2758931&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19720043%26dopt%3DAbstract In this study, using a newly established system, we three-dimensionally (3D) cultured rat skeletal myoblasts and loaded them with cyclic uniaxial tensile strain of different magnitudes or time duration. After that, the cell proliferative index (PI) and mRNA expression of MGF, IGF-IEa and integrin beta1 were assayed. The major findings are: 1) mechanical stimulation induced MGF upregulation commensurate with cell PI elevation both in the 3D and 2D cultured myoblasts, but stronger mechanical force was needed to activate MGF expression in the 3D cultures; 2) MGF but not IGF-IEa was essential for mechano-induced myoblast replication, as IGF-IEa upregulation lagged cell PI elevation; and 3) the time course upregulation of MGF and integrin beta1 was correlated with each other, suggesting they sh... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2758931 Thu, 27 Aug 2009 23:00:00 +0100 2758931 http://www.medworm.com/index.php?rid=2758930&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19720044%26dopt%3DAbstract Authors: Furuchi T, Suzuki T, Sekine M, Katane M, Homma H We have characterized release of D-aspartate (D-Asp), a regulator of hormone synthesis and secretion, via a volume-sensitive organic anion channel (VSOC) in PC12 cells by studying its response to apoptotic stimuli. PC12 cells have been demonstrated to endogenously synthesize D-Asp. Apoptotic inducers, including staurosporin (STS), tumor necrosis factor (TNF)-alpha, H(2)O(2), and C2-ceramide, activate the release of D-Asp through a hypotonic stimulus-triggered mechanism. Putative blockers of the anion channel, 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) and 4,4'-diisothiocyanostilbene-2, 2'-sulphonic acid (DIDS), significantly inhibited stress-induced D-Asp release under hypotonic conditions following the application of ap... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2758930 Thu, 27 Aug 2009 23:00:00 +0100 2758930 http://www.medworm.com/index.php?rid=2745773&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19712664%26dopt%3DAbstract Authors: Nikolaidis MG, Jamurtas AZ The exact origin of reactive species and oxidative damage detected in blood is largely unknown. Blood interacts with all organs and tissues and, consequently, with many possible sources of reactive species. In addition, a multitude of oxidizable substrates are already in blood. A muscle-centric approach is frequently adopted to explain reactive species generation, which obscures the possibility that sources of reactive species and oxidative damage other than skeletal muscle may be also at work during exercise. Plasma and blood cells can autonomously produce significant amounts of reactive species at rest and during exercise. The major reactive species generators located in blood during exercise may be erythrocytes (mainly due to their quantity) and l... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2745773 Sun, 23 Aug 2009 23:00:00 +0100 2745773 http://www.medworm.com/index.php?rid=2742005&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19706284%26dopt%3DAbstract Authors: Shifera AS, Hardin JA The herpes simplex virus type 1 (HSV-1) thymidine kinase (TK) promoter contains elements involved in both constitutive and induced expression. We determined that phorbol 12-myristate 13-acetate (PMA) induces the HSV-1 TK promoter in HEK293 cells. However, PMA did not induce expression from the promoter in HeLa cells and did not result in a globally increased gene expression in HEK293 cells. Induction of HSV-1 TK promoter required activation of both of JNK and ERK pathways. However, activation of the two pathways alone was not sufficient for induction of HSV-1 TK promoter. By transiently transfecting into HeLa cells the adenoviral E1A gene, which exists as an integrant in HEK293 genome, we demonstrated that E1A proteins are necessary for induction of HSV-1... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2742005 Fri, 21 Aug 2009 23:00:00 +0100 2742005 http://www.medworm.com/index.php?rid=2742004&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19706285%26dopt%3DAbstract Authors: Beca S, Aschar-Sobbi R, Ponjevic D, Winkfein RJ, Kargacin ME, Kargacin GJ Ca(2+) transport by the sarcoplasmic/endoplasmic reticulum Ca(2+) ATPase (SERCA) is sensitive to monovalent cations. Possible K(+) binding sites have been identified in both the cytoplasmic P-domain and the transmembrane transport-domain of the protein. We measured Ca(2+) transport into SR vesicles and SERCA ATPase activity in the presence of different monovalent cations. We found that the effects of monovalent cations on Ca(2+) transport correlated in most cases with their direct effects on SERCA. Choline(+), however, inhibited uptake to a greater extent than could be accounted for by its direct effect on SERCA suggesting a possible effect of choline on compensatory charge movement during Ca(2+) transpo... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2742004 Fri, 21 Aug 2009 23:00:00 +0100 2742004 http://www.medworm.com/index.php?rid=2735050&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19703407%26dopt%3DAbstract Authors: Guerrero-Mendiola C, Oria-Hernández J, Ramı Rez-Silva L In a previous study we found that 30-40% dimethylsulfoxide induces the active conformation of rabbit muscle pyruvate kinase. Because dimethylsulfoxide is known to perturb structure and function of many proteins, we have explored the effect of trehalose on the kinetics of thermal inactivation and stability of pyruvate kinase; this is because trehalose, in contrast to dimethyl sulfoxide, is totally excluded from the hydration shell of proteins. The results show that 600 mM trehalose inhibits the activity of pyruvate kinase by about 20 % at 25 degrees C, however trehalose protects pyruvate kinase from thermal inactivation at 60 degrees C, increases the Tm(app) of unfolding by 7.2 degrees C, induces a more compact ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2735050 Thu, 20 Aug 2009 23:00:00 +0100 2735050 http://www.medworm.com/index.php?rid=2735052&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19699176%26dopt%3DAbstract Authors: Markham GD, Takusagawa F, Dijulio AM, Bock CW Catalysis by S-adenosylmethionine synthetase has been investigated by quantum mechanical/molecular mechanical calculations, exploiting structures of the active crystalline enzyme. The transition state energy of +19.1 kcal/mol computed for a nucleophilic attack of the methionyl sulfur on carbon-5' of the nucleotide was indistinguishable from the experimental (solution) value when the QM residues were an uncharged histidine that hydrogen bonds to the leaving oxygen-5' and an aspartate that chelates a Mg(2+) ion, and was similar (+18.8 kcal/mol) when the QM region also included the active site arginine and lysines. The computed energy difference between reactant and product was also consistent with their equimolar abundance in co-crys... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2735052 Tue, 18 Aug 2009 23:00:00 +0100 2735052 http://www.medworm.com/index.php?rid=2735051&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19699177%26dopt%3DAbstract In conclusion, oridonin induces L929 cell G(2)/M arrest and apoptosis, which is regulated by promoting ERK-p53 apoptotic pathway and suppressing PTK-mediated survival pathway. PMID: 19699177 [PubMed - as supplied by publisher] (Source: Archives of Biochemistry and Biophysics) Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2735051 Tue, 18 Aug 2009 23:00:00 +0100 2735051 http://www.medworm.com/index.php?rid=2723595&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19695215%26dopt%3DAbstract In this study, the effects of norepinephrine on DNA synthesis and the related signaling molecules involved in rBMSCs were examined. mRNA levels of the alpha1-adrenergic receptor subtypes increased following norepinephrine stimulation (10(-5) M for 30 min). DNA synthesis increased in dose- and time-dependent manners as determined by [(3)H]thymidine incorporation. Intracellular Ca(2+) concentration and translocation of protein kinase C from the cytosol to the membrane were also found to be elevated in rBMSCs. Phentolamine was able to suppress translocation of PKC. Norepinephrine also induced phosphorylation of ERK1/2, which was prevented by staurosporine treatment. Pretreatment with PD98059 inhibited ERK1/2 phosphorylation and DNA synthesis in rBMSCs. These findings indicate that norepinephr... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2723595 Sun, 16 Aug 2009 23:00:00 +0100 2723595 http://www.medworm.com/index.php?rid=2723594&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19695216%26dopt%3DAbstract This study examined the question of whether deficiency of xCT, a cystine-transporter gene, exacerbates ischemia-reperfusion-induced acute renal failure (ARF). Two weeks after the right nephrectomy of male mice at 16-18 weeks of age, the left renal vessels were clamped for 45 min to induce renal ischemia. 24 h after induction of ischemia, xCT(-/-) mice had elevated concentrations of blood urea nitrogen and creatinine indicative of ARF, while in xCT(+/-) and xCT(+/+) mice, these parameters did not differ from the sham-operated mice. Immunohistochemical analyses of kidneys using antibodies against the oxidative stress markers revealed stronger staining in xCT(-/-) mice compared with xCT(+/+) mice. Induction of xCT mRNA in the kidneys of xCT(+/+) mice was demonstrated using reverse transcripta... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2723594 Sun, 16 Aug 2009 23:00:00 +0100 2723594 http://www.medworm.com/index.php?rid=2723593&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19695217%26dopt%3DAbstract Authors: Galán C, Zbidi H, Bartegi A, Salido GM, Rosado JA Ca(2+) entry, particularly store-operated Ca(2+) entry (SOCE), has been reported to be crucial for a variety of cellular functions. SOCE is a mechanism regulated by the Ca(2+) content of the stores, where the intraluminal Ca(2+) sensor STromal Interaction Molecule 1 (STIM1) has been reported to communicate the filling state of the intracellular Ca(2+) stores to the store-operated Ca(2+) permeable channels in the plasma membrane, likely involving Orai1 and TRPC proteins, such as TRPC1. Here we have investigated the role of Orai1, STIM1 and TRPC1 in platelet aggregation, an event that occurs during the process of thrombosis and hemostasis. Electrotransjection of cells with anti-STIM1 (25-139) antibody, directed towards the C... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2723593 Sun, 16 Aug 2009 23:00:00 +0100 2723593 http://www.medworm.com/index.php?rid=2720208&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19691144%26dopt%3DAbstract Mitochondrial malic enzyme (ME2) in pancreatic islets of the human, rat and mouse and clonal insulinoma cells. Arch Biochem Biophys. 2009 Aug 15;488(2):100-4 Authors: MacDonald MJ, Longacre MJ, Kendrick MA Despite interest in malic enzyme(ME)s in insulin cells, mitochondrial malic enzyme (ME2) has only been studied with estimates of mRNA or with mRNA knockdown. Because an mRNA's level does not necessarily reflect the level of its cognate enzyme, we designed a simple spectrophotometric enzyme assay to measure ME2 activity of insulin cells by utilizing the distinct kinetic properties of ME2. Mitochondrial ME2 uses either NAD or NADP as a cofactor, has a high Km for malate and is allosterically activated by fumarate and inhibited by ATP. Cytosolic ME (ME1) and the other mitochondr... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2720208 Fri, 14 Aug 2009 23:00:00 +0100 2720208 http://www.medworm.com/index.php?rid=2720207&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19691145%26dopt%3DAbstract In this study, phosphatidic acid (PA) metabolization is found to generate diacylglycerol (DAG), monoacylglycerol (MAG) and glycerol by the sequential action of lipid phosphate phosphatase (LPP), diacylglycerol lipase (DAGL), and monoacylglycerol lipase (MAGL) in cerebral cortex (CC) synaptosomes. It is also demonstrated that PA is metabolized by phospholipases A (PLA)/lysophosphatidic acid phosphohydrolase (LPAPase) in synaptic endings. Age-related changes in the metabolization of PA have been observed in rat cerebral cortex synaptosomes in the presence of the alternative substrates for LPP, namely LPA, sphingosine 1-phosphate (S1P) and ceramide 1-phosphate (C1P). In addition, LPA and C1P up to concentrations of about 50 microM favor the metabolism in the direction of MAG and glycerol in a... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2720207 Fri, 14 Aug 2009 23:00:00 +0100 2720207 http://www.medworm.com/index.php?rid=2712907&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19683506%26dopt%3DAbstract Authors: Hwang CC, Hsu CN, Huang TJ, Chiou SJ, Hong YR The dimerization of 3alpha-hydroxysteroid dehydrogenase/carbonyl reductase was studied by interrupting the salt bridge interactions between D249 and R167 in the dimeric interface. Substitution of alanine, lysine and serine for D249 decreased catalytic efficiency 30, 1400 and 1.4-fold, and lowered the melting temperature 6.9, 5.4 and 7.6 degrees C, respectively. The mutated enzymes have the dimeric species but the equilibrium between monomer and dimer for these mutants varies from each other, implying that these residues might contribute differently to the dimer stability. Thermal and urea-induced unfolding profiles for wild-type and mutant enzymes appeared as a two-state transition and three-state transition, respectively. In addit... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2712907 Wed, 12 Aug 2009 23:00:00 +0100 2712907 http://www.medworm.com/index.php?rid=2712906&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19683507%26dopt%3DAbstract Authors: Rapp J, Xu S, Sharp AM, Griffith WP, Kim YW, Funk MO The procedure for the expression and purification of recombinant porcine leukocyte 12-lipoxygenase using E. coli [K.M. Richards, L.J. Marnett, Biochemistry 36 (1997) 6692-6699] was updated to make it possible to produce enough protein for physical measurements. Electrospray ionization tandem mass spectrometry confirmed the amino acid sequence. The redox properties of the cofactor iron site were examined by EPR spectroscopy at 25 K following treatment with a variety of fatty acid hydroperoxides. Combination of the enzyme in a stoichiometric ratio with the hydroperoxides led to a g4.3 signal in EPR spectra instead of the g6 signal characteristic of similarly treated soybean lipoxygenase-1. Native 12-lipoxygenase was also subje... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2712906 Wed, 12 Aug 2009 23:00:00 +0100 2712906 http://www.medworm.com/index.php?rid=2712905&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19683508%26dopt%3DAbstract Authors: Tsukatani Y, Nakayama N, Shimada K, Mino H, Itoh S, Matsuura K, Hanada S, Nagashima KV A blue copper protein auracyanin of the filamentous anoxygenic phototroph Roseiflexus castenholzii was purified and characterized. Genomic sequence analysis showed that R. castenholzii has only one auracyanin, whereas Chloroflexus aurantiacus is known to have two auracyanins, A and B. Absorption spectrum of the Roseiflexus auracyanin was similar to that of auracyanin B of C.aurantiacus. On the other hand, ESR spectrum of the Roseiflexus auracyanin resembles that of auracyanin A of C. aurantiacus. These results suggest that the blue copper protein auracyanin from R. castenholzii shares features with each of auracyanin A and B. Amino acid sequence alignment of auracyanins from filamentous anox... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2712905 Wed, 12 Aug 2009 23:00:00 +0100 2712905 http://www.medworm.com/index.php?rid=2712904&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19683509%26dopt%3DAbstract Authors: Siggaard JH, Johansson E, Vognsen T, Helt SS, Harris P, Larsen S, Willemoës M Two mutant dCTP deaminase-dUTPases from Methanocaldococcus jannaschii were crystallised and the crystal structures were solved: E145A in complex with the substrate analog alpha,beta-imido-dUTP and E145Q in complex with diphosphate. Both mutant enzymes were defect in the deaminase reaction and had reduced dUTPase activity. In the structure of E145Q in complex with diphosphate, the diphosphate occupied the same position as the beta- and gamma-phosphoryls of the nucleotide analogue in the E145A complex. The C-terminal region that is unresolved in the apo-form of the enzyme was ordered in both complexes and closed over the active site by interacting with the phosphate backbone of the nucleotide or w... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2712904 Wed, 12 Aug 2009 23:00:00 +0100 2712904 http://www.medworm.com/index.php?rid=2712908&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19682972%26dopt%3DAbstract Authors: Guha P, Aneja KK, Shilpi RY, Haldar D We have recently identified two promoters, distal and proximal for rat mitochondrial glycerophosphate acyltransferase (mtGPAT). Here we are reporting further characterization of the promoters. Insulin and epidermal growth factor (EGF) stimulated while leptin and glucagon inhibited the luciferase activity of the distal promoter and the amounts of the distal transcript. Conversely, luciferase activity of the proximal promoter and proximal transcript remained unchanged due to these treatments. Only the distal promoter has binding sites for carbohydrate response element binding protein (ChREBP) and sterol regulatory element binding protein-1 (SREBP-1). Electromobility shift assays and chromatin immunoprecipitation assays demonstrated that ChRE... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2712908 Tue, 11 Aug 2009 23:00:00 +0100 2712908 http://www.medworm.com/index.php?rid=2703038&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19679098%26dopt%3DAbstract Authors: Gómez LA, Monette JS, Chavez JD, Maier CS, Hagen TM Accumulation of mitochondrial electron transport chain (ETC) defects is a recognized hallmark of the age-associated decline in cardiac bioenergetics; however, the molecular events involved are only poorly understood. In the present work, we hypothesized that age-related ETC deterioration stemmed partly from disassociation of large solid-state macromolecular assemblies termed "supercomplexes". Mitochondrial proteins from young and old rat hearts were separated by Blue Native-PAGE, protein bands analyzed by LC-MALDI-MS/MS, and protein levels quantified by densitometry. Results showed that supercomplexes comprised of various stoichiometries of complexes I, III and IV were observed, and declined significantly (p < 0.05, n... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2703038 Sun, 09 Aug 2009 23:00:00 +0100 2703038 http://www.medworm.com/index.php?rid=2696701&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19665987%26dopt%3DAbstract Authors: Zolfaghari R, Ross AC Lecithin:retinol acyltransferase (LRAT) is essential for vitamin A storage. Nuclear run-on assays demonstrated transcriptional regulation of the Lrat gene in vivo by all-trans-retinoic acid (RA) and other retinoids. Analysis of a 2.5 kb segment of rat genomic DNA revealed that the region approximately 300 bp upstream from the transcription start site (TSS) is necessary for high luciferase (Luc) reporter activity in HEK293T and HepG2 cells. Although this region lacks retinoid receptor binding elements, it responded to the nuclear receptors RARalpha, RARbeta or RARgamma, with RXRalpha with and without ligand. Removal of -111 bp from the TSS, which is well conserved in human, rat and mouse genomes, completely eliminated activity. This region contains several... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2696701 Thu, 06 Aug 2009 23:00:00 +0100 2696701 http://www.medworm.com/index.php?rid=2696702&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19664997%26dopt%3DAbstract Authors: Josephy PD, Kent M, Mannervik B We have previously expressed hexa-histidine-tagged human glutathione transferase GST T1-1 at very high levels in an E. colilacZ mutagenicity assay strain. Ethylene dibromide (EDB), which is activated by GST T1-1, produces a potent response in the mutation assay. We have now constructed and expressed two SNP variants of wild-type GST T1-1: D141N and E173K. The EDB activation activities of both variant enzymes, as measured by the lacZ mutagenicity assay, are greatly reduced The D141N variant behaved similarly to the wild-type enzyme, in terms of expression level and specific activities for conjugation of glutathione with 1,2-epoxy-3-(p-nitrophenoxy)propane (EPNP), ethylene diiodide (EDI), and 4-nitrobenzyl chloride (NBCl), and for peroxidative det... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2696702 Tue, 04 Aug 2009 23:00:00 +0100 2696702 http://www.medworm.com/index.php?rid=2696705&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19664586%26dopt%3DAbstract Authors: Gay SC, Fribourgh JL, Donohoue PD, Segel IH, Fisher AJ The Thiobacillus denitrificans genome contains two sequences corresponding to ATP sulfurylase (Tbd_0210 & Tbd_0874). Both genes were cloned and expressed protein characterized. The larger protein (Tbd_0210; 544 residues) possesses an N-terminal ATP sulfurylase domain and a C-terminal APS kinase domain and was therefore annotated as a bifunctional enzyme. But, the protein was not bifunctional because it lacked ATP sulfurylase activity. However, the enzyme did possess APS kinase activity and displayed substrate inhibition by APS. Truncated protein missing the N-terminal domain had < 2% APS kinase activity suggesting the function of the inactive sulfurylase domain is to promote the oligomerization of the APS kinase dom... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2696705 Mon, 03 Aug 2009 23:00:00 +0100 2696705 http://www.medworm.com/index.php?rid=2696704&cid=s_34394_60_f&fid=34394&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D19664587%26dopt%3DAbstract In this study, we measured the enzymatic parameters for TruD in E.coli, and carried out enzymatic assays for a series of single, double, and triple TruD mutants. Our studies indicate that a Glu, strictly conserved in only TruD family is likely to be the general base in TruD. We also proposed a possible distinct mechanism of TruD-catalyzed Psi formation compared to the first four families. PMID: 19664587 [PubMed - as supplied by publisher] (Source: Archives of Biochemistry and Biophysics) Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=2696704 Mon, 03 Aug 2009 23:00:00 +0100 2696704