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. Thu, 09 Feb 2012 13:38:26 +0100 http://www.medworm.com/index.php?rid=5672779&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%3D22310642%26dopt%3DAbstract Authors: Dunn MF Abstract The tryptophan synthase α(2)β(2) bi-enzyme complex catalyzes the last two steps in the synthesis of l-tryptophan (l-Trp). The α-subunit catalyzes cleavage of 3-indole-d-glycerol 3'-phosphate (IGP) to give indole and d-glyceraldehyde 3'-phosphate (G3P). Indole is then transferred (channeled) via an interconnecting 25Å-long tunnel, from the α-subunit to the β-subunit where it reacts with l-Ser in a pyridoxal 5'-phosphate-dependent reaction to give l-Trp and a water molecule. The efficient utilization of IGP and l-Ser by tryptophan synthase to synthesize l-Trp utilizes a system of allosteric interactions that (1) function to switch the α-site on and off at different stages of the β-subunit catalytic cycle, and (2) prevent the escape of the channeled i... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5672779 Thu, 02 Feb 2012 05:00:00 +0100 5672779 http://www.medworm.com/index.php?rid=5637317&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%3D22264738%26dopt%3DAbstract Authors: Fitzpatrick P, Sies H PMID: 22264738 [PubMed - in process] (Source: Archives of Biochemistry and Biophysics) Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5637317 Sat, 28 Jan 2012 22:36:23 +0100 5637317 http://www.medworm.com/index.php?rid=5637311&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%3D22266245%26dopt%3DAbstract We describe results of early investigations that endeavored to trap and detect this elusive monooxygenating species, as well as results of experiments that attempted to generate and characterize this active oxidant spectroscopically after reacting ferric P450 enzymes with peroxy compounds (e.g. peroxides, peracids) or single oxygen atom donors (e.g. periodate, iodosobenzene). Surrogate oxidants were able to promote P450-catalyzed monooxygenations in a manner similar to that of O(2)/NAD(P)H, suggesting involvement of a common transitory monooxygenating species in the two pathways. This common P450 oxidant was characterized as a porphyrin radical iron(IV) oxo complex and assigned a Compound I structure (Por(+)Fe(IV)=O) exhibiting a formal Fe(V) oxidation state. Other reactive oxidants, such ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5637311 Fri, 13 Jan 2012 05:00:00 +0100 5637311 http://www.medworm.com/index.php?rid=5619240&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%3D22248627%26dopt%3DAbstract Authors: Aragão EA, Vieira DS, Chioato L, Ferreira TL, Lourenzoni MR, Silva SR, Ward RJ Abstract Suramin is a polysulphonated naphthylurea with inhibitory activity against the human secreted group IIA phospholipase A(2) (hsPLA2GIIA), and we have investigated suramin binding to recombinant hsPLA2GIIA using site-directed mutagenesis and molecular dynamics (MD) simulations. The changes in suramin binding affinity of 13 cationic residue mutants of the hsPLA2GIIA was strongly correlated with alterations in the inhibition of membrane damaging activity of the protein. Suramin binding to hsPLA2GIIA was also studied by MD simulations, which demonstrated that altered intermolecular potential energy of the suramin/mutant complexes was a reliable indicator of affinity change. Although residue... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5619240 Tue, 10 Jan 2012 05:00:00 +0100 5619240 http://www.medworm.com/index.php?rid=5619244&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%3D22244832%26dopt%3DAbstract Authors: Jorge SE, Petruk AA, Kimura EM, Oliveira DM, Caire L, Suemasu CN, Silveira PA, Albuquerque DM, Costa FF, Skaf MS, Martínez L, de Fatima Sonati M Abstract Hb S-São Paulo (SP) [HBB:c.20A>T p.Glu6Val; c.196A>G p.Lys65Glu] is a new double-mutant hemoglobin that was found in heterozygosis in an 18-month-old Brazilian male with moderate anemia. It behaves like Hb S in acid electrophoresis, isoelectric focusing and solubility testing but shows different behavior in alkaline electrophoresis, cation-exchange HPLC and RP-HPLC. The variant is slightly unstable, showed reduced oxygen affinity and also appeared to form polymers more stable than the Hb S. Molecular dynamics simulation suggests that the polymerization is favored by interfacial electrostatic interactions. This pro... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5619244 Sun, 08 Jan 2012 05:00:00 +0100 5619244 http://www.medworm.com/index.php?rid=5619243&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%3D22244833%26dopt%3DAbstract Authors: Kawano M, Miyamoto K, Kaito Y, Sumimoto H, Tamura M Abstract Noxa1 was discovered as an activating factor for Nox1, an O(2)(-)-generating enzyme. Subsequent studies have shown that Noxa1 is colocalized with Nox2 in several cell types, including vascular cells. Nox2 activation by Noxa1 has been examined in reconstituted model cells. However, little is known about the kinetic properties of Noxa1 in Nox2 activation. In the present study, we used purified cyt.b(558) (Nox2 plus p22(phox)), Rac(Q61L), and Noxo1 to examine the ability of Noxa1 to activate Nox2. In the pure reconstitution system, Noxa1 activated Nox2 with lower efficiency than p67(phox), a canonical activator of Nox2. The EC(50) value of Noxa1 was considerably higher than that of p67(phox). The V(max) value with N... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5619243 Sun, 08 Jan 2012 05:00:00 +0100 5619243 http://www.medworm.com/index.php?rid=5619242&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%3D22244834%26dopt%3DAbstract Authors: Inbar NH, Benhar I Abstract More than 2 dozen years had passed since the field of antibody engineering was established, with the first reports of bacterial [1-3] and mammalian cells [4] expression of recombinant antibody fragments, and in that time a lot of effort was dedicated to the development of efficient technological means, intended to assist in the creation of therapeutic monoclonal antibodies (mAbs). Research focus was given to two intertwined technological aspects: the selection platform and the recombinant antibody repertoires. In accordance with these areas of interest, it is the goal of this chapter to describe the various selection tools and antibody libraries existing, with emphasis on the later, and their applications. This chapter gives a far from exhaustiv... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5619242 Sun, 08 Jan 2012 05:00:00 +0100 5619242 http://www.medworm.com/index.php?rid=5619241&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%3D22245335%26dopt%3DAbstract Authors: Denisov IG, Sligar SG Abstract Cooperative functional properties and allosteric regulation in cytochromes P450 play an important role in xenobiotic metabolism and define one of the main mechanisms of drug-drug interactions. Recent experimental results suggest that ability to bind simultaneously two or more small organic molecules can be the essential feature of cytochrome P450 fold, and often results in rich and complex pattern of allosteric behavior. Manifestations of non-Michaelis kinetics include homotropic and heterotropic activation and inhibition effects depending on the stoichiometric ratios of substrate and effector, changes in the regio- and stereospecificity of catalytic transformations, and often give rise to the clinically important drug-drug interactions. In a... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5619241 Sun, 08 Jan 2012 05:00:00 +0100 5619241 http://www.medworm.com/index.php?rid=5596037&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%3D22239988%26dopt%3DAbstract Authors: Loft S, Danielsen P, Løhr M, Jantzen K, Hemmingsen JG, Roursgaard M, Karotki DG, Møller P Abstract Oxidatively damaged DNA may be important in carcinogenesis. 8-Oxo-7,8-dihydroguanine (8-oxoGua) is an abundant and mutagenic lesion excised by oxoguanine DNA glycosylase 1 (OGG1) and measurable in urine or plasma by chromatographic methods with electrochemical or mass spectrometric detectors, reflecting the rate of damage in steady state. A common genetic OGG1 variant may affect the activity and was associated with increased levels of oxidized purines in leukocytes without apparent effect on 8-oxoGua excretion or major change in cancer risk. 8-OxoGua excretion has been associated with exposure to air pollution, toxic metals, tobacco smoke and low plasma antioxidant levels, ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5596037 Wed, 04 Jan 2012 05:00:00 +0100 5596037 http://www.medworm.com/index.php?rid=5596136&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%3D22230326%26dopt%3DAbstract Authors: Peradziryi H, Tolwinski NS, Borchers A Abstract PTK7 (protein tyrosine kinase 7) is an evolutionarily conserved transmembrane receptor with functions in various processes ranging from embryonic morphogenesis to epidermal wound repair. Here, we review recent findings indicating that PTK7 is a versatile co-receptor that functions as a molecular switch in Wnt, Semaphorin/Plexin and VEGF signaling pathways. We focus in particular on the role of PTK7 in Wnt signaling, as recent data indicate that PTK7 acts as a Wnt co-receptor, which activates the planar cell polarity pathway, but inhibits canonical Wnt signaling. PMID: 22230326 [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=5596136 Tue, 03 Jan 2012 05:00:00 +0100 5596136 http://www.medworm.com/index.php?rid=5596074&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%3D22230328%26dopt%3DAbstract Authors: Lezcano V, Bellido T, Plotkin LI, Boland R, Morelli S Abstract Bisphosphonates (BPs) inhibit osteocyte and osteoblast apoptosis via opening of connexin (Cx) 43 hemichannels and activating the extracellular signal regulated kinases ERKs. Previously, we hypothesized that intracellular survival signaling is initiated by interaction of BPs with Cx43. However, using whole cell binding assays with [(3)H]-alendronate, herein we demonstrated the presence of saturable, specific and high affinity binding sites in the Cx43-expressing ROS 17/2.8 osteoblastic cells, authentic osteoblasts and MLO-Y4 cells expressing Cx43 or not, as well as in HeLa cells lacking Cx43 expression and ROS 17/2.8 cells pretreated with agents that disassemble Cx channels. In addition, both BPs and the PTP inh... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5596074 Tue, 03 Jan 2012 05:00:00 +0100 5596074 http://www.medworm.com/index.php?rid=5596055&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%3D22234250%26dopt%3DAbstract Authors: Lai Y, Song M, Hakala K, Weintraub ST, Shiio Y Abstract Inactivation of the von Hippel-Lindau (VHL) tumor suppressor is associated with renal carcinoma, hemangioblastoma and pheochromocytoma. The VHL protein is a component of a ubiquitin ligase complex that ubiquitinates and degrades hypoxia inducible factor-α (HIF-α). Degradation of HIF-α by VHL is proposed to suppress tumorigenesis and tumor angiogenesis. Several lines of evidence also suggest important roles for HIF-independent VHL functions in tumor suppression and other biological processes. Using GST-VHL pull-down experiment and mass spectrometry, we detected an interaction between VHL and heterochromatin protein 1 (HP1). We identified a conserved HP1-binding motif (PXVXL) in the β domain of VHL, which is disrupt... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5596055 Tue, 03 Jan 2012 05:00:00 +0100 5596055 http://www.medworm.com/index.php?rid=5596042&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%3D22239987%26dopt%3DAbstract Authors: Abbrescia DI, Piana GL, Lofrumento NE Abstract In mammalian cells aerobic oxidation of glucose requires reducing equivalents produced in glycolytic phase to be channelled into the phosphorylating respiratory chain for the reduction of molecular oxygen. Data never presented before show that the oxidation rate of exogenous NADH supported by the malate-aspartate shuttle system (reconstituted in vitro with isolated liver mitochondria) is comparable to the rate obtained on activation of the cytosolic NADH/cytochrome c electron transport pathway. The activities of these two reducing equivalent transport systems are independent of each other and additive. NADH oxidation induced by the malate-aspartate shuttle is inhibited by aminooxyacetate and by rotenone and/or antimycin A, two... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5596042 Tue, 03 Jan 2012 05:00:00 +0100 5596042 http://www.medworm.com/index.php?rid=5596036&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%3D22239989%26dopt%3DAbstract Authors: Su V, Lau AF Abstract Gap junction channels provide a conduit for communication between neighboring cells. The function of gap junction channels is regulated by posttranslational modifications of connexins, the proteins that comprise these channels. Ubiquitination of connexins has increasingly been viewed as one mechanism by which cells regulate the level of connexins present in cells, as well as the corresponding intercellular communication. Here we review the current knowledge of connexin ubiquitination and the effects this may have on gap junctional communication. PMID: 22239989 [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=5596036 Tue, 03 Jan 2012 05:00:00 +0100 5596036 http://www.medworm.com/index.php?rid=5596121&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%3D22230327%26dopt%3DAbstract This article emphasizes studies that have provided new insight related to the mechanisms involved in the intestinal actions of 1,25(OH)(2)D(3). The following are discussed: recent studies, including those using knock out mice, that suggest that 1,25(OH)(2)D(3) mediated calcium absorption is more complex than the traditional transcellular model; evidence for 1,25(OH)(2)D(3) mediated active transport of calcium by distal as well as proximal segments of the intestine; 1,25(OH)(2)D(3) regulation of paracellular calcium transport and the role of 1,25(OH)(2)D(3) in protection against mucosal injury. PMID: 22230327 [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=5596121 Mon, 02 Jan 2012 05:00:00 +0100 5596121 http://www.medworm.com/index.php?rid=5596061&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%3D22230329%26dopt%3DAbstract Authors: Vendel MC, Favis M, Snyder WB, Huang F, Capili AD, Dong J, Glaser SM, Miller BR, Demarest SJ Abstract Escherichia coli (E. coli) is the most commonly used organism for expressing antibody fragments such as single chain antibody Fvs (scFvs). Previously, we have utilized E. coli to express well-folded scFvs for characterization and engineering purposes with the goal of using these engineered proteins as building blocks for generating IgG-like bispecific antibodies (BsAbs). In the study, described here, we observed a significant difference in the secondary structure of an scFv produced in E. coli and the same scFv expressed and secreted from chinese hamster ovary (CHO) cells as part of a BsAb. We devised a proteolytic procedure to separate the CHO-derived scFv from its antibo... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5596061 Mon, 02 Jan 2012 05:00:00 +0100 5596061 http://www.medworm.com/index.php?rid=5596150&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%3D22227097%26dopt%3DAbstract Authors: Heo GY, Liao WL, Turko IV, Pikuleva IA Abstract The retina is the sensory organ in the back of the eye which absorbs and converts light to electrochemical impulses transferred to the brain. Herein, we studied how retinal environment affects enzyme-mediated cholesterol removal. We focused on two mitochondrial cytochrome P450 enzymes, CYPs 27A1 and 11A1, which catalyze the first steps in metabolism of cholesterol in the retina and other tissues. Phospholipids (PL) from mitochondria of bovine neural retina, retinal pigment epithelium, liver and adrenal cortex were isolated and compared for the effect on kinetic properties of purified recombinant CYPs in the reconstituted system in vitro. The four studied tissues were also evaluated for the mitochondrial PL and cholesterol con... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5596150 Thu, 29 Dec 2011 05:00:00 +0100 5596150 http://www.medworm.com/index.php?rid=5596142&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%3D22227098%26dopt%3DAbstract Authors: Williams CK, Vathiyalingam S, Hammel M, Pipas J, Chazin WJ Abstract Simian Virus 40 uses the large T antigen (Tag) to bind and inactivate retinoblastoma tumor suppressor proteins (Rb), which can result in cellular transformation. Tag is a modular protein with four domains connected by flexible linkers. The N-terminal J domain of Tag is necessary for Rb inactivation. Binding of Rb is mediated by an LXCXE consensus motif immediately C-terminal to the J domain. Nuclear magnetic resonance (NMR) and small angle X-ray scattering (SAXS) were used to study the structural dynamics and interaction of Rb with the LXCXE motif, the J domain and a construct (N(260)) extending from the J domain through the origin binding domain (OBD). NMR and SAXS data revealed substantial flexibility be... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5596142 Thu, 29 Dec 2011 05:00:00 +0100 5596142 http://www.medworm.com/index.php?rid=5596173&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%3D22226857%26dopt%3DAbstract Authors: Kumagai T, Ishino T, Nakagawa Y Abstract Electrophiles in environmental pollutants or cigarette smoke are high risk factors for various diseases caused by cell injuries such as apoptosis and inflammation. Here we show that electrophilic compounds such as diethyl malate (DEM), methyl mercury and cigarette smoke extracts significantly enhanced the expression of acidic sphingomyelinase (ASMase). ASMase activity and the amount of ceramide of DEM-treated cells were approximately 6 times and 4 times higher than these of non-treated cells, respectively. Moreover, we found that DEM pretreatment enhanced the production of IL-6 induced by TNF-α. Knockdown of ASMase attenuated the enhancement of TNF-α-dependent IL-6 production. On the other hand, enhancement of TNF-α-induced IL-6 ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5596173 Tue, 27 Dec 2011 05:00:00 +0100 5596173 http://www.medworm.com/index.php?rid=5558049&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%3D22209752%26dopt%3DAbstract Authors: Díaz A, Loewen PC, Fita I, Carpena X Abstract About thirty years ago the crystal structures of the heme catalases from Penicillium vitale (PVC) and, a few months later, from bovine liver (BLC) were published. Both enzymes were compact tetrameric molecules with subunits that, despite their size differences and the large phylogenetic separation between the two organisms, presented a striking structural similarity for about 460 residues. The high conservation, confirmed in all the subsequent structures determined, suggested a strong pressure to preserve a functional catalase fold, which is almost exclusively found in these mono-functional heme catalases. However, even in the absence of the catalase fold an efficient catalase activity is also found in the heme containing cata... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5558049 Fri, 23 Dec 2011 05:00:00 +0100 5558049 http://www.medworm.com/index.php?rid=5558048&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%3D22209753%26dopt%3DAbstract Authors: Lekka M, Gil D, Pogoda K, Dulińska-Litewka J, Jach R, Gostek J, Klymenko O, Prauzner-Bechcicki S, Stachura Z, Wiltowska-Zuber J, Okoń K, Laidler P Abstract Currently, cancer diagnosis relies mostly on morphological examination of exfoliated, aspirated cells or surgically removed tissue. As long as standard diagnosis is concerned, this classical approach seems to be satisfactory. In the recent years, cancer progression has been shown to be accompanied by alterations in mechanical properties of cells. This offers the detection of otherwise unnoticed cancer cell disregarded by histological analysis due to insignificant manifestations. One of techniques, sensitive to changes in mechanical properties, is the atomic force microscopy, which detects cancer cells through their el... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5558048 Fri, 23 Dec 2011 05:00:00 +0100 5558048 http://www.medworm.com/index.php?rid=5558047&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%3D22209754%26dopt%3DAbstract Authors: Park AM, Hayakawa S, Honda E, Mine Y, Yoshida K, Munakata H Abstract Pulmonary fibrosis is a devastating condition resulting from excess extracellular matrix deposition that leads to progressive lung destruction and scarring. In the pathogenesis of fibrotic diseases, activation of myofibroblasts by transforming growth factor-β (TGF-β) plays a crucial role. Since no effective therapy for pulmonary fibrosis is currently recognized, finding an effective antifibrotic agent is an important objective. One approach might be through identification of agents that inactivate myofibroblasts. In the current study we examined the potential of conditioned medium obtained from several types of cells to exhibit myofibroblast inactivating activity. Conditioned media from lung cancer cell... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5558047 Fri, 23 Dec 2011 05:00:00 +0100 5558047 http://www.medworm.com/index.php?rid=5558050&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%3D22206618%26dopt%3DAbstract This study provides indubitable evidence that the combination of CB5R and Cyt-b5 is an alternative redox partner facilitating the monooxygenase reaction catalyzed by CYP5150A2. PMID: 22206618 [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=5558050 Tue, 20 Dec 2011 05:00:00 +0100 5558050 http://www.medworm.com/index.php?rid=5558052&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%3D22203089%26dopt%3DAbstract Authors: Takano K, Sato K, Negishi Y, Aramaki Y Abstract We clarified whether actin cytoskeleton is involved in the macrophage apoptosis induced by cationic liposomes composed of stearylamine (SA-liposomes). Externalization of phosphatidylserine induced by SA-liposomes was suppressed by cytochalasin D, a specific inhibitor of polymerization of F-actin. Furthermore, activation of PKCδ and reactive oxygen species (ROS) generation, which could be involved in the macrophage apoptosis, were inhibited by cytochalasin D. Microscopical observation revealed the co-localization of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI)-labeled SA-liposomes and fluorescein-labeled phalloidin, which specifically binds to F-actin, and this co-localization was also inhibited by... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5558052 Mon, 19 Dec 2011 05:00:00 +0100 5558052 http://www.medworm.com/index.php?rid=5558051&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%3D22203090%26dopt%3DAbstract Authors: Zhao B, Bellamine A, Lei L, Waterman MR Abstract Both CYP158A1 and CYP158A2 are able to catalyze an oxidative C-C coupling reaction producing biflaviolin or triflaviolin in Streptomyces coelicolor A3(2). The substrate-bound crystal structures of CYP158A2 and CYP158A1 reveal that the side chain of Ile87 in CYP158A2 points to the active site contacting the distal flaviolin molecule, however, the bulkier side chain of Lys90 in CYP158A1 (corresponding to Ile87 in CYP158A2) is toward the distal surface of the protein. These results suggest that these residues could be important in determining product regiospecificity. In order to explore the role of the two residues in catalysis, the reciprocal mutants, Ile87Lys and Lys90Ile, of CYP158A2 and CYP158A1, respectively, were generat... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5558051 Mon, 19 Dec 2011 05:00:00 +0100 5558051 http://www.medworm.com/index.php?rid=5545051&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%3D22198279%26dopt%3DAbstract Authors: Manley G, Loria JP Abstract Allosterism is one of nature's principal methods for regulating protein function. Allosterism utilizes ligand binding at one site to regulate the function of the protein by modulating the structure and dynamics of a distant binding site. In this review, we first survey solution NMR techniques and how they may be applied to the study of allostery. Subsequently, we describe several examples of application of NMR to protein allostery and highlight the unique insight provided by this experimental technique. PMID: 22198279 [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=5545051 Fri, 16 Dec 2011 05:00:00 +0100 5545051 http://www.medworm.com/index.php?rid=5545050&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%3D22198280%26dopt%3DAbstract Authors: Le K, Li R, Xu S, Wu X, Huang H, Bao Y, Cai Y, Lan T, Moss J, Li C, Zou J, Shen X, Liu P Abstract Peroxisome proliferator-activated receptor alpha (PPARα) has been implicated in the pathogenesis of cardiac hypertrophy, although its mechanism of action remains largely unknown. To determine the effect of PPARα activation on endothelin-1 (ET-1)-induced cardiomyocyte hypertrophy and explore its molecular mechanisms, we evaluated the interaction of PPARα with nuclear factor of activated T-cells c4 (NFATc4) in nuclei of cardiomyocytes from neonatal rats in primary culture. In ET-1-stimulated cardiomyocytes, data from electrophoretic mobility-shift assays (EMSA) and co-immunoprecipitation (co-IP) revealed that fenofibrate (Fen), a PPARα activator, in a concentration-dependent... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5545050 Fri, 16 Dec 2011 05:00:00 +0100 5545050 http://www.medworm.com/index.php?rid=5545049&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%3D22198281%26dopt%3DAbstract Authors: Peng P, Mei GD, Salim M, Jing C, Jing Z, Ya ZX, Jing ZN, Jing X, Hong J Abstract Metabolic syndrome is a low-grade inflammatory state in which oxidative stress is involved. Naringin, isolated from the Citrussinensis, is a phenolic compound with anti-oxidative and anti-inflammatory activities. The aim of this study was to explore the effects of naringin on metabolic syndrome in mice. The animal models, induced by high-fat diet in C57BL/6 mice, developed obesity, dyslipidemia, fatty liver, liver dysfunction and insulin resistance. These changes were attenuated by naringin. Further investigations revealed that the inhibitory effect on inflammation and insulin resistance was mediated by blocking activation of the MAPKs pathways and by activating IRS1; the lipid-lowering effect... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5545049 Fri, 16 Dec 2011 05:00:00 +0100 5545049 http://www.medworm.com/index.php?rid=5545048&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%3D22198282%26dopt%3DAbstract Authors: Kutuzova GD, Gabelt BT, Kiland JA, Hennes-Beann EA, Kaufman PL, Deluca HF Abstract Ocular hypertension is the greatest known risk factor for glaucoma that affects an estimated 70million people worldwide. Lowering intraocular pressure (IOP) remains the mainstay of therapy in the management of glaucoma. By means of microarray analysis, we have discovered that 1α,25-dihydroxyvitamin D(3) (1α,25-(OH)(2)D(3)) regulates genes that are known to be involved in the determination of intraocular pressure (IOP). Topical administration of 1α,25-(OH)(2)D(3) or its analog, 2-methylene-19-nor-(20S)-1α,25-dihydroxyvitamin D(3) (2MD), markedly reduce IOP in non-human primates. The reduction in IOP is not the result of reduced aqueous humor formation, while a 35% increase in aqueous humo... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5545048 Fri, 16 Dec 2011 05:00:00 +0100 5545048 http://www.medworm.com/index.php?rid=5545047&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%3D22198283%26dopt%3DAbstract Authors: Kantrowitz ER Abstract The allosteric enzyme aspartate transcarbamoylase (ATCase) from Escherichia coli has been the subject of investigations for approximately 50years. This enzyme controls the rate of pyrimidine nucleotide biosynthesis by feedback inhibition, and helps to balance the pyrimidine and purine pools by competitive allosteric activation by ATP. The catalytic and regulatory components of the dodecameric enzyme can be separated and studied independently. Many of the properties of the enzyme follow the Monod, Wyman Changeux model of allosteric control thus E. coli ATCase has become the textbook example. This review will highlight kinetic, biophysical, and structural studies which have provided a molecular level understanding of how the allosteric nature of this e... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5545047 Fri, 16 Dec 2011 05:00:00 +0100 5545047 http://www.medworm.com/index.php?rid=5545046&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%3D22198284%26dopt%3DAbstract Authors: Vaughan CA, Singh S, Windle B, Sankala HM, Graves PR, Andrew Yeudall W, Deb SP, Deb S Abstract Cancer cells with p53 mutations, in general, grow more aggressively than those with wild-type p53 and show "gain of function" (GOF) phenotypes such as increased growth rate, enhanced resistance to chemotherapeutic drugs, increased cell motility and tumorigenicity; although the mechanism for this function remains unknown. In this communication we report that p53-mediated NF-κB2 up-regulation significantly contributes to the aggressive oncogenic behavior of cancer cells. Lowering the level of mutant p53 in a number of cancer cell lines resulted in a loss of GOF phenotypes directly implicating p53 mutants in the process. RNAi against NF-κB2 in naturally occurring cancer cell lines... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5545046 Fri, 16 Dec 2011 05:00:00 +0100 5545046 http://www.medworm.com/index.php?rid=5545045&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%3D22198285%26dopt%3DAbstract Authors: Whittaker JW Abstract Non-heme manganese catalases are widely distributed over microbial life and represent an environmentally important alternative to heme-containing catalases in antioxidant defense. Manganese catalases contain a binuclear manganese complex as their catalytic active site rather than a heme, and cycle between Mn(2)(II,II) and Mn(2)(III,III) states during turnover. X-ray crystallography has revealed the key structural elements of the binuclear manganese active site complex that can serve as the starting point for computational studies on the protein. Four manganese catalase enzymes have been isolated and characterized, and the enzyme appears to have a broad phylogenetic distribution including both bacteria and archae. More than 100 manganese catalase genes... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5545045 Fri, 16 Dec 2011 05:00:00 +0100 5545045 http://www.medworm.com/index.php?rid=5545044&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%3D22198286%26dopt%3DAbstract Authors: Barak Z, Chipman DM Abstract Acetohydroxyacid Synthases (AHASs) have separate small regulatory subunits which specifically activate the catalytic subunits with which they are associated. The binding sites for the inhibitory amino acid(s) (valine or leucine) are in the interface between two ACT (small ligand binding) domains, and are apparently found in all AHAS regulatory subunits. However, the structures and the kinetic mechanisms of the different enzymes are very heterogeneous. Among the three isozymes encoded in the enterobacteria, the regulatory patterns are different, and their different responses to the inhibitory end product valine can be rationalized, at least in part, on the basis of the regulatory subunit structures and differences in catalytic mechanisms. The re... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5545044 Fri, 16 Dec 2011 05:00:00 +0100 5545044 http://www.medworm.com/index.php?rid=5545052&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%3D22197458%26dopt%3DAbstract Authors: Campo GM, Avenoso A, D'Ascola A, Prestipino V, Scuruchi M, Nastasi G, Calatroni A, Campo S Abstract Hyaluronan (HA) fragments are able to induce inflammation by stimulating both CD44 and toll-like receptor 4 (TLR-4). CD44 and TLR-4 activation stimulates the liberation of NF-kB and a pro-inflammatory cytokine responses. The aim of this study was to investigate the effects of hyaluronidase (HYAL) treatment, which depolymerises HA into small fragments, and of the addition of specific hyaluronan synthases-1, 2, and 3 small interference RNA (HASs siRNA), which silenced HASs activity, on normal mouse synovial fibroblasts (NSF) and on rheumatoid arthritis synovial fibroblasts (RASF) obtained from mice subjected to collagen induced arthritis (CIA). The addition of HYAL to NSF and/... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5545052 Wed, 14 Dec 2011 05:00:00 +0100 5545052 http://www.medworm.com/index.php?rid=5527107&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%3D22182753%26dopt%3DAbstract Authors: Reinehr R, Häussinger D Abstract Recent evidence suggests that signaling pathways towards cell proliferation and cell death are much more interconnected than previously thought. Whereas not only death receptors such as CD95 (Fas, APO-1) can couple to both, cell death and proliferation, also growth factor receptors such as the epidermal growth factor receptor (EGFR) are involved in these opposing kinds of cell fate. EGFR is briefly discussed as a growth factor receptor involved in liver cell proliferation during liver regeneration. Then the role of EGFR in activating CD95 death receptor in liver parenchymal cells (PC) and hepatic stellate cells (HSC), which represent a liver stem/progenitor cell compartment, is described summarizing different ways of CD95- and EGFR-depende... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5527107 Tue, 13 Dec 2011 05:00:00 +0100 5527107 http://www.medworm.com/index.php?rid=5527106&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%3D22182754%26dopt%3DAbstract Authors: Selwood T, Jaffe EK Abstract Homo-oligomeric protein assemblies are known to participate in dynamic association/disassociation equilibria under native conditions, thus creating an equilibrium of assembly states. Such quaternary structure equilibria may be influenced in a physiologically significant manner either by covalent modification or by the non-covalent binding of ligands. This review follows the evolution of ideas about homo-oligomeric equilibria through the 20th and into the 21st centuries and the relationship of these equilibria to allosteric regulation by the non-covalent binding of ligands. A dynamic quaternary structure equilibria is described where the dissociated state can have alternate conformations that cannot reassociate to the original multimer; the alte... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5527106 Tue, 13 Dec 2011 05:00:00 +0100 5527106 http://www.medworm.com/index.php?rid=5527112&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%3D22178560%26dopt%3DAbstract This study provides morpho-functional data of right and left thyroid lobes by biochemical, immunohistochemistry, immunoblotting and immunofluorescence analysis. We demonstrate that, in comparison with the left lobe, the right lobe has a higher activation index, is more sensitive to thyrotropin treatment, is rich in thyrotropin receptor and caveolin 1 involved in thyroid hormone synthesis as well as in epithelial thyroid cell homeostasis, is characterised by a high content of molecules involved in cell signalling such as stat3, raf1, sphingomyelinase and sphingomyelin-synthase whose activity ratio is necessary for epithelial cell activity and finally has more areas calcitonin-dependent. The relation between structure/function of right lobe and its susceptibility to the higher risk of pathol... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5527112 Fri, 09 Dec 2011 05:00:00 +0100 5527112 http://www.medworm.com/index.php?rid=5527110&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%3D22179017%26dopt%3DAbstract Authors: de Paula FJ, Rosen CJ Abstract Vitamin D an ancient secosteroid is essential for mineral homeostasis, bone remodeling, immune modulation, and energy metabolism. Recently, debates have emerged about the daily vitamin D requirements for healthy and elderly adults, the safety and efficacy of long term supplementation and the role of vitamin D deficiency in several chronic disease states. Since this molecule acts as both a vitamin and a hormone, it should not be surprising that the effects of supplementation are multi-faceted and complex. Yet despite significant progress in the last decade, our understanding of vitamin D physiology and the clinical relevance of low circulating levels of this vitamin remains incomplete. The present review provides the reader with a comprehensiv... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5527110 Fri, 09 Dec 2011 05:00:00 +0100 5527110 http://www.medworm.com/index.php?rid=5527109&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%3D22179018%26dopt%3DAbstract Authors: Smith MA, Schnellmann RG Abstract Calpain 10 is ubiquitously expressed and is one of four mitochondrial matrix proteases. We determined that over-expression or knock-down of mitochondrial calpain 10 results in cell death, demonstrating that mitochondrial calpain 10 is required for viability. Thus, we studied calpain 10 degradation in isolated mitochondrial matrix, mitochondria and in renal proximal tubular cells (RPTC) under control and toxic conditions. Using isolated renal cortical mitochondria and mitochondrial matrix, calpain 10 underwent rapid degradation at 37°C that was blocked with Lon inhibitors but not by calpain or proteasome inhibitors. While exogenous Ca(2+) addition, Ca(2+) chelation or exogenous ATP addition had no effect on calpain 10 degradation, the oxid... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5527109 Fri, 09 Dec 2011 05:00:00 +0100 5527109 http://www.medworm.com/index.php?rid=5527108&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%3D22179019%26dopt%3DAbstract In this report, we explore the mechanism of this regulation using recently developed ChIP-chip and ChIP-seq techniques that permit an unbiased search for enhancer elements that participate in this transcriptional control. Our studies both confirm a regulatory region defined earlier and located proximal to the transcriptional start site (TSS) of mouse Cyp24a1 (-160 and -265nt) and identify a novel intergenic region located downstream of the transcription unit that contains two enhancers (+35 and +37kb) that facilitate 1,25(OH)(2)D(3)-dependent upregulation of Cyp24a1 expression. Interestingly, while C/EBPβ also binds under basal conditions to a site located immediately upstream of the Cyp24a1 promoter (-345nt), occupancy by this factor is strikingly increased following 1,25(OH)(2)D(3) trea... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5527108 Fri, 09 Dec 2011 05:00:00 +0100 5527108 http://www.medworm.com/index.php?rid=5527113&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%3D22172685%26dopt%3DAbstract Authors: Jha V, Donald LJ, Loewen PC Abstract The monofunctional catalase KatE of Esherichia coli exhibits exceptional resistance to heat denaturation and proteolytic degradation. During an investigation of subtle conformation changes in Arg111 and Phe413 on the proximal side of the heme induced by H(2)O(2), variants at position R111, T115 and F413 were constructed. Because the residues are not situated in the distal side heme cavity where catalysis occurs, significant changes in reactivity were not expected and indeed, only small changes in the kinetic characteristics were observed in all of the variants. However, the F413Y variant was found to have undergone main chain cleavage whereas the R111A, T115A, F413E and F413K variants had not. Two sites of cleavage were identified in th... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5527113 Thu, 08 Dec 2011 05:00:00 +0100 5527113 http://www.medworm.com/index.php?rid=5527111&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%3D22178748%26dopt%3DAbstract Authors: Guerra AJ, Giedroc DP Abstract All prokaryotes encode a panel of metal sensor or metalloregulatory proteins that govern the expression of genes that allows an organism to quickly adapt to toxicity or deprivation of both biologically essential transition metal ions, e.g., Zn, Cu, Fe, and heavy metal pollutants. As such, metal sensor proteins can be considered arbiters of intracellular transition metal bioavailability and thus potentially control the metallation state of the metalloproteins in the cell. Metal sensor proteins are specialized allosteric proteins that regulate transcription as a result direct binding of one or two cognate metal ions, to the exclusion of all others. In most cases, the binding of the cognate metal ion induces a structural change in a protein olig... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5527111 Thu, 08 Dec 2011 05:00:00 +0100 5527111 http://www.medworm.com/index.php?rid=5527114&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%3D22155656%26dopt%3DAbstract Authors: Hasan NM, Longacre MJ, Stoker S, Kendrick MA, Druckenbrod NR, Laychock SG, Mastrandrea LD, Macdonald MJ Abstract To evaluate the role of sphingosine kinase 1 (SphK1) in insulin secretion, we used stable transfection to knock down the expression of the Sphk1 gene in the rat insulinoma INS-1 832/13 cell line. Cell lines with lowered Sphk1 mRNA expression and SphK1 enzyme activity (SK11 and SK14) exhibited lowered glucose- and 2-aminobicyclo[2,2,1]heptane-2-carboxylic acid (BCH) plus glutamine-stimulated insulin release and low insulin content associated with decreases in the mRNA of the insulin 1 gene. Overexpression of the rat or human Sphk1 cDNA restored insulin secretion and total insulin content in the SK11 cell line, but not in the SK14 cell line. The Sphk1 cDNA-transfe... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5527114 Sun, 04 Dec 2011 05:00:00 +0100 5527114 http://www.medworm.com/index.php?rid=5527116&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%3D22155150%26dopt%3DAbstract In this study we found that low doses of oridonin, an active diterpenoid, enhanced phagocytosis of apoptotic cells by human macrophage-like U937 cells, meanwhile it also induced autophagy in these U937 cells. Moreover, inhibition of extracellular signal-related kinase (ERK), nuclear factor-κB (NF-κB) and caspase-1 significantly suppressed oridonin-induced phagocytosis and autophagy. In addition, oridonin increased the protein levels of p-ERK, NF-κB, caspase-1 and pro IL-1β. Autophagic inhibitor 3-methyladenine (3-MA) decreased phagocytosis and the expression of ERK whereas increased the expression of NF-κB- and caspase-1-mediated IL-1β release. Beclin-1 (known as autophagic regulator) loss also led to the similar results. Pretreatment with autophagic agonist rapamycin caused opposite... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5527116 Fri, 02 Dec 2011 05:00:00 +0100 5527116 http://www.medworm.com/index.php?rid=5527115&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%3D22155151%26dopt%3DAbstract Authors: Liu NQ, Hewison M Abstract Impaired vitamin D status is common to many populations around the world. However, data suggest that this is a particular problem for specific groups such as pregnant women. This has raised important questions concerning the physiological and clinical impact of low vitamin D levels during pregnancy, with implications for classical skeletal functions of vitamin D, as well as its diverse non-classical actions. The current review will discuss this with specific emphasis on the classical calciotropic effects of vitamin D as well as the less well established immunological functions of vitamin D that may influence pregnancy outcome. The review also describes the pathways that are required for metabolism and function of vitamin D, and the various clinic... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5527115 Fri, 02 Dec 2011 05:00:00 +0100 5527115 http://www.medworm.com/index.php?rid=5527117&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%3D22155115%26dopt%3DAbstract Authors: Jancewicz LJ, Wheatley RW, Sutendra G, Lee M, Fraser ME, Huber RE Abstract A loop (residues 794-803) at the active site of β-galactosidase (Escherichia coli) opens and closes during catalysis. The α and β carbons of Ser-796 form a hydrophobic connection to Phe-601 when the loop is closed while a connection via two H-bonds with the Ser hydroxyl occurs with the loop open. β-Galactosidases with substitutions for Ser-796 were investigated. Replacement by Ala strongly stabilizes the closed conformation because of greater hydrophobicity and loss of H-bonding ability while replacement with Thr stabilizes the open form through hydrophobic interactions with its methyl group. Upon substitution with Asp much of the defined loop structure is lost. The different open-closed equilib... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5527117 Thu, 01 Dec 2011 05:00:00 +0100 5527117 http://www.medworm.com/index.php?rid=5489492&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%3D22138222%26dopt%3DAbstract Authors: Malaisse WJ, Zhang Y, Louchami K, Sharma S, Dresselaers T, Himmelreich U, Novotny GW, Mandrup-Poulsen T, Waschke D, Leshch Y, Thimm J, Thiem J, Sener A Abstract Suitable analogs of d-mannoheptulose are currently considered as possible tools for the non-invasive imaging of pancreatic islet insulin-producing cells. Here, we examined whether (19)F-heptuloses could be used for non-invasive imaging of GLUT2-expressing cells. After 20min incubation, the uptake of (19)F-heptuloses (25mM) by rat hepatocytes, as assessed by (19)F NMR spectroscopy, ranged from 0.50 (1-deoxy-1-fluoro-d-mannoheptulose and 3-deoxy-3-fluoro-d-mannoheptulose) to 0.25 (1,3-dideoxy-1,3-difluoro-d-mannoheptulose) and 0.13 (1-deoxy-1-fluoro-d-glucoheptulose, 3-deoxy-3-fluoro-d-glucoheptulose and 1,3-dideoxy-... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489492 Tue, 22 Nov 2011 05:00:00 +0100 5489492 http://www.medworm.com/index.php?rid=5489493&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%3D22120519%26dopt%3DAbstract We describe how the binding of acetyl CoA produces gross changes to the quaternary and tertiary structures of the enzyme that are visible in the electron microscope. These changes serve to stabilize the tetrameric structure of the enzyme. The main locus of activation of the enzyme by acetyl CoA is the biotin carboxylation domain of the enzyme where ATP-cleavage and carboxylation of the biotin prosthetic group occur. As well as enhancing reaction rates, acetyl CoA also enhances the binding of some substrates, especially HCO(3)(-), and there is also a complex interaction with the binding of the cofactor Mg(2+). The activation of pyruvate carboxylase by acetyl CoA is generally a cooperative processes, although there is a large degree of variability in the degree of cooperativity exhibited by ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489493 Sat, 19 Nov 2011 05:00:00 +0100 5489493 http://www.medworm.com/index.php?rid=5489494&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%3D22119138%26dopt%3DAbstract Authors: Franco TM, Rostirolla DC, Ducati RG, Lorenzini DM, Basso LA, Santos DS Abstract Administration of the current tuberculosis (TB) vaccine to newborns is not a reliable route for preventing TB in adults. The conversion of XMP to GMP is catalyzed by guaA-encoded GMP synthetase (GMPS), and deletions in the Shiguella flexneri guaBA operon led to an attenuated auxotrophic strain. Here we present the cloning, expression, and purification of recombinant guaA-encoded GMPS from Mycobacterium tuberculosis (MtGMPS). Mass spectrometry data, oligomeric state determination, steady-state kinetics, isothermal titration calorimetry (ITC), and multiple sequence alignment are also presented. The homodimeric MtGMPS catalyzes the conversion of XMP, MgATP, and glutamine into GMP, ADP, PP(i), and ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489494 Fri, 18 Nov 2011 05:00:00 +0100 5489494 http://www.medworm.com/index.php?rid=5489501&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%3D22100759%26dopt%3DAbstract Authors: Folda A, Citta A, Scutari G, Bindoli A, Rigobello MP Abstract The effects of selenite and tellurite on the mammalian enzyme lipoamide dehydrogenase were compared. Selenite acts as a substrate of lipoamide dehydrogenase in a process requiring the presence of lipoamide. In contrast, tellurite is a potent inhibitor, effective in the low micromolar range. The inhibitory effect of tellurite on lipoamide dehydrogenase is partially reverted by dithiothreitol indicating the participation of the thiol groups of the enzyme. Tellurite, but not selenite, stimulates the diaphorase activity of lipoamide dehydrogenase. In a mitochondrial matrix protein preparation, which contains lipoamide dehydrogenase, an inhibitory action similar to that observed on the purified enzyme was also elicit... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489501 Tue, 15 Nov 2011 05:00:00 +0100 5489501 http://www.medworm.com/index.php?rid=5489500&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%3D22107946%26dopt%3DAbstract Authors: Glebocka A, Chiellini G Abstract The growing interest in1α,25(OH)(2)D(3), the hormonally active form of vitamin D(3), has prompted numerous efforts to synthesize vitamin D analogs as potential therapeutic agents, and some of these are already on the market and in clinical development. Although most vitamin D preparations developed thus far have focused on side-chain modifications, providing many useful analogues with high potency and selectivity, in recent years, modifications of the A-ring has attracted much attention because it can afford useful analogues exhibiting unique activity profiles as well. In this review we will focus on the current understanding of the relationship between selected modifications in the A-ring of the 1α,25(OH)(2)D(3) molecule, such as epimeri... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489500 Tue, 15 Nov 2011 05:00:00 +0100 5489500 http://www.medworm.com/index.php?rid=5489499&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%3D22107947%26dopt%3DAbstract Authors: Larion M, Miller BG Abstract Glucokinase catalyzes the ATP-dependent phosphorylation of glucose, a chemical transformation that represents the rate-limiting step of glycolytic metabolism in the liver and pancreas. Glucokinase is a central regulator of glucose homeostasis as evidenced by its association with two disease states, maturity onset diabetes of the young (MODY) and persistent hyperinsulinemia of infancy (PHHI). Mammalian glucokinase is subject to homotropic allosteric regulation by glucose - the steady-state velocity of glucose-6-phosphate production is not hyperbolic, but instead displays a sigmoidal response to increasing glucose concentrations. The positive cooperativity displayed by glucokinase is intriguing since the enzyme functions as a monomer under physio... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489499 Tue, 15 Nov 2011 05:00:00 +0100 5489499 http://www.medworm.com/index.php?rid=5489498&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%3D22107948%26dopt%3DAbstract Authors: White JH Abstract Vitamin D was discovered as the cure for nutritional rickets. Classically, hormonal 1,25-dihydroxyvitamin D (1,25D), produced in the kidney by CYP27B1-catalyzed 1α-hydroxylation from its circulating 25-hydroxy precursor, has been considered to function as a critical endocrine regulator of calcium homeostasis. However, our appreciation of vitamin D metabolism and physiological function has evolved dramatically in recent years. First, vitamin D is now recognized as a pleiotropic regulator of human physiology, with emerging roles in cancer chemoprevention, cardio-protection, and, in particular, regulation of immune system functions. Moreover, CYP27B1 is very widely expressed, and evidence is rapidly accumulating that local CYP27B1-catalyzed production of 1,... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489498 Tue, 15 Nov 2011 05:00:00 +0100 5489498 http://www.medworm.com/index.php?rid=5489497&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%3D22107949%26dopt%3DAbstract Authors: Senga Y, Nagamine T, Kameshita I, Sueyoshi N Abstract We isolated cDNA clones for zebrafish Ca(2+)/calmodulin-dependent protein kinase I (zCaMKI) δ isoforms by expression screening using cDNA library from embryos at 72-h post-fertilization (hpf). There are two splice variants with different C-terminal sequences, comprising of 392 and 368 amino acids, and they are designated zCaMKIδ-L (long form) and zCaMKIδ-S (short form), respectively. Although recombinant zCaMKIδ-L and zCaMKIδ-S expressed in Escherichia coli showed essentially the same catalytic properties including substrate specificities, they showed different spatial and temporal expression. Western blotting analysis using the isoform-specific antibodies revealed that zCaMKIδ-L clearly appeared from 36hpf but zC... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489497 Tue, 15 Nov 2011 05:00:00 +0100 5489497 http://www.medworm.com/index.php?rid=5489496&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%3D22107950%26dopt%3DAbstract Authors: Suda T, Takahashi F, Takahashi N Abstract Vitamin D was discovered as an anti-rachitic agent, but even at present, there is no direct evidence to support the concept that vitamin D directly stimulates osteoblastic bone formation and mineralization. It appears to be paradoxical, but vitamin D functions in the process of osteoclastic bone resorption. In 1952, Carlsson reported that administration of vitamin D(3) to rats fed a vitamin D-deficient, low calcium diet raised serum calcium levels. Since the diet did not contain appreciable amounts of calcium, the rise in serum calcium was considered to be derived from bone. Since then, this assay has been used as a standard bioassay for vitamin D compounds. Osteoclasts, the cells responsible for bone resorption, develop from hemat... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489496 Tue, 15 Nov 2011 05:00:00 +0100 5489496 http://www.medworm.com/index.php?rid=5489495&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%3D22119137%26dopt%3DAbstract Authors: Yue H, Kang Y, Zhang H, Gao X, Blankenship RE Abstract Heliobacterium modesticaldum is a Gram-positive, anaerobic, anoxygenic photoheterotrophic bacterium. Its cytochrome bc complex (Rieske/cyt b complex) has some similarities to cytochrome b(6)f complexes from cyanobacteria and chloroplasts, and also shares some characteristics of typical bacterial cytochrome bc(1) complexes. One of the unique factors of the heliobacterial cytochrome bc complex is the presence of a diheme cytochrome c instead of the monoheme cytochrome f in the cytochrome b(6)f complex or the monoheme cytochrome c(1) in the bc(1) complex. To understand the structure and function of this diheme cytochrome c protein, we expressed the N-terminal transmembrane-helix-truncated soluble H. modesticaldum diheme c... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489495 Tue, 15 Nov 2011 05:00:00 +0100 5489495 http://www.medworm.com/index.php?rid=5489505&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%3D22100522%26dopt%3DAbstract Authors: Jones G, Prosser D, Kaufmann M Abstract CYP24A1 is the cytochrome P450 component of the 25-hydroxyvitamin D(3)-24-hydroxylase enzyme that catalyzes the conversion of 25-hydroxyvitamin D(3) (25-OH-D(3)) and 1,25-dihydroxyvitamin D(3) (1,25-(OH)(2)D(3)) into 24-hydroxylated products, which constitute the degradation of the vitamin D molecule. This review focuses on recent data in the CYP24A1 field, including biochemical, physiological and clinical developments. Notable among these are: the first crystal structure for rat CYP24A1; mutagenesis studies which change the regioselectivity of the enzyme; and the finding that natural inactivating mutations of CYP24A1 cause the genetic disease idiopathic infantile hypercalcemia (IIH). The review also discusses the emerging correlatio... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489505 Sat, 12 Nov 2011 05:00:00 +0100 5489505 http://www.medworm.com/index.php?rid=5489504&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%3D22100703%26dopt%3DAbstract Authors: Wen H, Kang S, Song Y, Song Y, Yang HJ, Kim MH, Park S Abstract FKBP12, an FK506 binding protein, interacts with type 1 ryanodine receptor (RyR1) and modulates its calcium channel activity. However, there are many opposing reports of FKBP12's interaction with other related calcium channels, such as type 1 IP(3) receptor and type 3 ryanodine receptor (IP(3)R1 and RyR3). In addition, the involvement of the prolyl-dipeptide motif in the calcium channels and the corresponding binding residues in FKBP12 remain controversial. Through pulldown assays with recombinant proteins, we provide biochemical evidence of the interaction between FKBP12 and RyR1, RyR3 and IP(3)R1. Using NMR chemical shift mapping, we show that the important binding residues in FKBP12 are located in its hydro... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489504 Fri, 11 Nov 2011 05:00:00 +0100 5489504 http://www.medworm.com/index.php?rid=5489503&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%3D22100704%26dopt%3DAbstract Authors: Szoleczky P, Módis K, Nagy N, Dóri Tóth Z, Dewitt D, Szabó C, Gerő D Abstract Acute tubular necrosis is a clinical problem that lacks specific therapy and is characterized by high mortality rate. The ischemic renal injury affects the proximal tubule cells causing dysfunction and cell death after severe hypoperfusion. We utilized a cell-based screening approach in a hypoxia-reoxygenation model of tubular injury to search for cytoprotective action using a library of pharmacologically active compounds. Oxygen-glucose deprivation (OGD) induced ATP depletion, suppressed aerobic and anaerobic metabolism, increased the permeability of the monolayer, caused poly(ADP-ribose) polymerase cleavage and caspase-dependent cell death. The only compound that proved cytoprotective eith... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489503 Fri, 11 Nov 2011 05:00:00 +0100 5489503 http://www.medworm.com/index.php?rid=5489502&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%3D22100705%26dopt%3DAbstract In this study, we found that zebrafish CaMKP-N (zCaMKP-N) underwent proteolytic processing in both the zebrafish brain and Neuro2a cells. In Neuro2a cells, the proteolytic processing was effectively inhibited by the proteasome inhibitors MG-132, Epoxomicin, and Lactacystin, suggesting that the ubiquitin-proteasome pathway was involved in this processing. Using MG-132, we found that the proteolytic processing changed the subcellular localization of zCaMKP-N from the nucleus to the cytosol. Accompanying this change, the cellular targets of zCaMKP-N in Neuro2a cells were significantly altered. Furthermore, we obtained evidence that the zCaMKP-N activity was markedly activated when the C-terminal domain was removed by the processing. Thus, the proteolytic processing of zCaMKP-N at the C-termin... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489502 Fri, 11 Nov 2011 05:00:00 +0100 5489502 http://www.medworm.com/index.php?rid=5489508&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%3D22093697%26dopt%3DAbstract Authors: Hartley MD, Imperiali B Abstract Long-chain polyprenols and polyprenyl-phosphates are ubiquitous and essential components of cellular membranes throughout all domains of life. Polyprenyl-phosphates, which include undecaprenyl-phosphate in bacteria and the dolichyl-phosphates in archaea and eukaryotes, serve as specific membrane-bound carriers in glycan biosynthetic pathways responsible for the production of cellular structures such as N-linked protein glycans and bacterial peptidoglycan. Polyprenyl-phosphates are the only form of polyprenols with a biochemically-defined role; however, unmodified or esterified polyprenols often comprise significant percentages of the cellular polyprenol pool. The strong evolutionary conservation of unmodified polyprenols as membrane constit... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489508 Thu, 10 Nov 2011 05:00:00 +0100 5489508 http://www.medworm.com/index.php?rid=5489507&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%3D22093698%26dopt%3DAbstract Authors: Bridges CC, Krasnikov BF, Joshee L, Pinto JT, Hallen A, Li J, Zalups RK, Cooper AJ Abstract Anthropogenic practices and recycling in the environment through natural processes result in release of potentially harmful levels of mercury into the biosphere. Mercury, especially organic forms, accumulates in the food chain. Mercury reacts readily with sulfur-containing compounds and often exists as a thiol S-conjugate, such as the l-cysteine (Cys)-S-conjugate of methylmercury (CH(3)Hg-S-Cys) or inorganic mercury (Cys-S-Hg-S-Cys). These S-conjugates are structurally similar to l-methionine and l-cystine/l-cystathionine, respectively. Bovine and rat glutamine transaminase K (GTK) catalyze transamination of sulfur-containing amino acids. Recombinant human GTK (rhGTK) has a relative... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489507 Thu, 10 Nov 2011 05:00:00 +0100 5489507 http://www.medworm.com/index.php?rid=5489506&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%3D22093699%26dopt%3DAbstract In this study, we confirmed increase in ABCG2 mRNA levels in human hepatocytes after adenoviral expression of hCAR and treatment with its activator. Reporter assays suggested the existence of an hCAR-responsive element between -8000 and -7485 of hABCG2 promoter. Electrophoretic mobility shift assays and chromatin immunoprecipitation assays identified a DR5 motif (direct repeat separated by five nucleotides) within the region as a binding motif of hCAR/human retinoid X receptor α heterodimer. The introduction of mutations into the DR5 motif resulted in the complete loss of the hCAR-mediated transactivation. Interestingly, human pregnane X receptor, belonging to the same NR1I subfamily as CAR, did not activate any reporter gene containing the DR5 motif. Taken together, our present findings ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5489506 Thu, 10 Nov 2011 05:00:00 +0100 5489506 http://www.medworm.com/index.php?rid=5414570&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%3D22085500%26dopt%3DAbstract Authors: Cantorna MT Abstract It has now been more than 20years since the vitamin D receptor was identified in cells of the immune system. The immune system has now been established as an important target of vitamin D. Vitamin D receptor knockout and vitamin D deficient mice have a surplus of effector T cells that have been implicated in the pathology of multiple sclerosis (MS) and inflammatory bowel disease (IBD). The active form of vitamin D directly and indirectly suppresses the function of these pathogenic T cells while inducing several regulatory T cells that suppress MS and IBD development. There is reason to believe that vitamin D could be an environmental factor that may play a role in the development of these immune mediated diseases in the clinic but at present there has ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5414570 Thu, 10 Nov 2011 05:00:00 +0100 5414570 http://www.medworm.com/index.php?rid=5414572&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%3D22085498%26dopt%3DAbstract Authors: Kuphal S, Bosserhoff AK Abstract Cell-cell communication is necessary for the crosstalk between cells that constitute multicellular organisms and is essential for cells to coordinate their physiological behavior to create cohesive tissues. Cellular crosstalk is not only controlled by molecules, like growth factors, hormones, ions and G-proteins, etc. but also by cell-cell contacts. These contacts are essential for intercellular communication and are involved in survival, apoptosis, proliferation, differentiation and homeostasis of entire tissues. In polarized epithelia of vertebrates, the adherent junction is part of the tripartite junctional complex that is localized at the juxtaluminal region, which includes tight junctions (including claudins, occludins, and zonula occl... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5414572 Wed, 09 Nov 2011 05:00:00 +0100 5414572 http://www.medworm.com/index.php?rid=5414571&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%3D22085499%26dopt%3DAbstract Authors: Welsh J Abstract Epidemiologic data suggest that the incidence and severity of many types of cancer inversely correlates with indices of vitamin D status. The vitamin D receptor (VDR) is highly expressed in epithelial cells at risk for carcinogenesis including those resident in skin, breast, prostate and colon, providing a direct molecular link by which vitamin D status impacts on carcinogenesis. Consistent with this concept, activation of VDR by its ligand 1,25-dihydroxyvitamin D (1,25D) triggers comprehensive genomic changes in epithelial cells that contribute to maintenance of the differentiated phenotype, resistance to cellular stresses and protection of the genome. Many epithelial cells also express the vitamin D metabolizing enzyme CYP27B1 which enables autocrine gen... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5414571 Wed, 09 Nov 2011 05:00:00 +0100 5414571 http://www.medworm.com/index.php?rid=5414569&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%3D22086120%26dopt%3DAbstract Authors: Bystranowska D, Szewczuk Z, Lisowski M, Sitkiewicz E, Dobryszycki P, Ożyhar A, Kochman M Abstract Juvenile hormone binding protein (JHBP) acts as a shuttle, carrying one of the most crucial hormones for insect development to target tissues. We have found that although the JHBP molecule does not contain tryptophan residues, it exhibits a weak fluorescence maximum near 420nm upon excitation at 315nm. Gel filtration experiments performed in denaturing conditions and ESI-MS analyses excluded the possibility that some low molecular ligand was bound to the protein molecules. Further UV and CD spectroscopy studies, as well as immunoblotting, showed that the unusual JHBP optical properties were due to dityrosine intramolecular cross-linking. These bridges were detected both in na... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5414569 Wed, 09 Nov 2011 05:00:00 +0100 5414569 http://www.medworm.com/index.php?rid=5414573&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%3D22079167%26dopt%3DAbstract Authors: Dumas R, Cobessi D, Robin AY, Ferrer JL, Curien G Abstract Based on recent X-ray structures and biochemical characterizations of aspartate kinases from different species, we show in this review how various organizations of a regulatory domain have contributed to the different mechanisms of control observed in aspartate kinases allowing simple to complex allosteric controls in branched pathways. The aim of this review is to show the relationships between domain organization, effector binding sites, mechanism of inhibition and regulatory function of an allosteric enzyme in a biosynthetic pathway. PMID: 22079167 [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=5414573 Sun, 06 Nov 2011 04:00:00 +0100 5414573 http://www.medworm.com/index.php?rid=5414574&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%3D22079166%26dopt%3DAbstract Authors: Li M, Li C, Allen A, Stanley CA, Smith TJ Abstract Glutamate dehydrogenase (GDH) is a homohexameric enzyme that catalyzes the reversible oxidative deamination of l-glutamate to 2-oxoglutarate. Only in the animal kingdom is this enzyme heavily allosterically regulated by a wide array of metabolites. The major activators are ADP and leucine, while the most important inhibitors include GTP, palmitoyl CoA, and ATP. Recently, spontaneous mutations in the GTP inhibitory site that lead to the hyperinsulinism/hyperammonemia (HHS) syndrome have shed light as to why mammalian GDH is so tightly regulated. Patients with HHS exhibit hypersecretion of insulin upon consumption of protein and concomitantly extremely high levels of ammonium in the serum. The atomic structures of four new i... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5414574 Fri, 04 Nov 2011 04:00:00 +0100 5414574 http://www.medworm.com/index.php?rid=5414575&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%3D22056482%26dopt%3DAbstract Authors: Gorudko IV, Mukhortava AV, Caraher B, Ren M, Cherenkevich SN, Kelly GM, Timoshenko AV Abstract The gp91phox subunit of flavocytochrome b(558) is the catalytic core of the phagocyte plasma membrane NADPH oxidase. Its activation occurs within lipid rafts and requires translocation of four subunits to flavocytochrome b(558). gp91phox is the only glycosylated subunit of NADPH oxidase and no data exist about the structure or function of its glycans. Glycans, however, bind to lectins and this can stimulates NADPH oxidase activity. Given this information, we hypothesized that lectin-gp91phox interactions would facilitate the assembly of a functionally active NADPH oxidase in the absence of lipid rafts. To test this, we used lectins with different carbohydrate-binding specificity ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5414575 Fri, 28 Oct 2011 04:00:00 +0100 5414575 http://www.medworm.com/index.php?rid=5377393&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%3D22040654%26dopt%3DAbstract Authors: Moxley MA, Tanner JJ, Becker DF Abstract The multifunctional proline utilization A (PutA) flavoenzyme from Escherichia coli performs the oxidation of proline to glutamate in two catalytic steps using separate proline dehydrogenase (PRODH) and Δ(1)-pyrroline-5-carboxylate (P5C) dehydrogenase domains. In the first reaction, the oxidation of proline is coupled to the reduction of ubiquinone (CoQ) by the PRODH domain, which has a β(8)α(8)-barrel structure that is conserved in bacterial and eukaryotic PRODH enzymes. The structural requirements of the benzoquinone moiety were examined by steady-state kinetics using CoQ analogs. PutA displayed activity with all the analogs tested; the highest k(cat)/K(m) was obtained with CoQ(2). The kinetic mechanism of the PRODH reaction was... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5377393 Tue, 25 Oct 2011 04:00:00 +0100 5377393 http://www.medworm.com/index.php?rid=5377392&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%3D22050912%26dopt%3DAbstract Authors: Imaizumi N, Aniya Y Abstract We have previously shown that the mitochondrial membrane-bound glutathione transferase (mtMGST1) is activated via thiol modifications and contributes to the mitochondrial permeability transition (MPT) pore. In the present study we aimed to confirm the role of mtMGST1 in the oxidant peroxynitrite (PON)-induced MPT pore opening. PON induced the swelling of mitoplasts (inner membranes including the matrix) as well as of the mitochondria. The swelling was markedly suppressed by ADP [an adenine nucleotide translocator (ANT) ligand] and partially suppressed by cyclosporin A or by GST inhibitors (tannic acid, S-hexylglutathione). Dithiothreitol (DTT), a disulfide bond-reducing reagent, prevented the swelling. Western blot analyses of mitoplast protein... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5377392 Sat, 22 Oct 2011 04:00:00 +0100 5377392 http://www.medworm.com/index.php?rid=5377395&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%3D22037355%26dopt%3DAbstract Authors: Koshiishi I, Yokota A, Takajo T Abstract Nitric oxide (()NO) is thought to react with fatty acid alkoxyl radical, which is generated from fatty acid hydroperoxide via one-electron reduction. However, detail in the reaction remains obscure. In the present study, we examined the reaction of nitric oxide with fatty acid alkoxyl radical generated in the lipoxygenase/linoleate/13-hydroperoxyoctadecadienoate (13-HpODE) system under anaerobic conditions via HPLC equipped with mass spectrometry and photodiode array detections. In this reaction system, nitric oxide can scavenge linoleate alkoxyl radical, producing 13-ONO-9Z,11E-ODE. However, instead of 13-ONO-9Z,11E-ODE, 13-NO-9E,11E-ODE and 9-NO-10E,12E-ODE were alternatively detected in the reaction solution. To explain this cont... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5377395 Wed, 19 Oct 2011 04:00:00 +0100 5377395 http://www.medworm.com/index.php?rid=5377394&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%3D22037356%26dopt%3DAbstract Authors: Jaffe EK, Lawrence SH Abstract The structural basis for allosteric regulation of porphobilinogen synthase (PBGS) is modulation of a quaternary structure equilibrium between octamer and hexamer (via dimers), which is represented schematically as 8mer ⇔ 2mer ⇔ 2mer(*)⇔ 6mer(*). The "(*)" represents a reorientation between two domains of each subunit that occurs in the dissociated state because it is sterically forbidden in the larger multimers. Allosteric effectors of PBGS are both intrinsic and extrinsic and are phylogenetically variable. In some species this equilibrium is modulated intrinsically by magnesium which binds at a site specific to the 8mer. In other species this equilibrium is modulated intrinsically by pH; the guanidinium group of an arginine being spati... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5377394 Wed, 19 Oct 2011 04:00:00 +0100 5377394 http://www.medworm.com/index.php?rid=5358343&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%3D22033339%26dopt%3DAbstract Authors: Frantom PA Abstract The manipulation of modular regulatory domains from allosteric enzymes represents a possible mechanism to engineer allostery into non-allosteric systems. Currently, there is insufficient understanding of the structure/function relationships in modular regulatory domains to rationally implement this methodology. The LeuA dimer regulatory domain represents a well-conserved, novel fold responsible for the regulation of two enzymes involved in branched chain amino acid biosynthesis, α-isopropylmalate synthase and citramalate synthase. The LeuA dimer regulatory domain is responsible for the feedback inhibition of these enzymes by their respective downstream products. Both enzymes display multidomain architecture with a conserved N-terminal TIM barrel cataly... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5358343 Wed, 19 Oct 2011 04:00:00 +0100 5358343 http://www.medworm.com/index.php?rid=5358342&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%3D22033340%26dopt%3DAbstract Authors: Castelli S, Vassallo O, Katkar P, Che CM, Sun RW, Desideri A Abstract A gold(III) compound [Au(C^N^C)(IMe)]CF(3)SO(3) (Gold III) has been reported to have anticancer properties as it is able to reduce topoisomerase IB activity in vitro and suppress tumor growth in nude mice model. Here we have investigated the mechanism of inhibition of human topoisomerase IB activity by this compound, analyzing the various steps of the catalytic cycle. DNA supercoiled relaxation and the cleavage reaction are inhibited, but Gold III does not perturb the religation reaction, in contrast to what has been observed for camptothecin. Pre-incubation of enzyme with the inhibitor before adding DNA substrate increases the inhibitory effect. In addition, when Gold III is preincubated with the enzyme... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5358342 Wed, 19 Oct 2011 04:00:00 +0100 5358342 http://www.medworm.com/index.php?rid=5358344&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%3D22027029%26dopt%3DAbstract Authors: Singh N, Kuppili RR, Bose K Abstract HtrA (High temperature requirement protease A) proteins that are primarily involved in protein quality control belong to a family of serine proteases conserved from bacteria to humans. HtrAs are oligomeric proteins that share a common trimeric pyramidal architecture where each monomer comprises a serine protease domain and one or two PDZ domains. Although the overall structural integrity is well maintained and they exhibit similar mechanism of activation, subtle conformational changes and structural plasticity especially in the flexible loop regions and domain interfaces lead to differences in their active site conformation and hence in their specificity and functions. PMID: 22027029 [PubMed - as supplied by publisher] (Source: Arch... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5358344 Tue, 18 Oct 2011 04:00:00 +0100 5358344 http://www.medworm.com/index.php?rid=5358347&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%3D22019820%26dopt%3DAbstract In conclusion, care must be taken when using FHRE-Luc to assess FoxO activity in response to stimuli that potentially interfere with xenobiotic signaling. PMID: 22019820 [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=5358347 Sat, 15 Oct 2011 04:00:00 +0100 5358347 http://www.medworm.com/index.php?rid=5358345&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%3D22023909%26dopt%3DAbstract Authors: Grant GA Abstract d-3-Phosphoglycerate dehydrogenases (PGDH) exist with at least three different structural motifs and the enzymes from different species display distinctly different mechanisms. In many species, particularly bacteria, the catalytic activity is regulated allosterically through binding of l-serine to a distinct structural domain, termed the ACT domain. Some species, such as Mycobacterium tuberculosis, contain an additional domain, called the "allosteric substrate binding" or ASB domain, that functions as a co-domain in the regulation of catalytic activity. That is, both substrate and effector function synergistically in the regulation of activity to give the enzyme some interesting properties that may have physiological relevance for the persistent state of ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5358345 Sat, 15 Oct 2011 04:00:00 +0100 5358345 http://www.medworm.com/index.php?rid=5358346&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%3D22019940%26dopt%3DAbstract Authors: Mandraju R, Chekuri A, Bhaskar C, Duning K, Kremerskothen J, Kondapi AK Abstract In the present study, the activity of Topoisomerase IIβ (TopoIIβ) is evaluated during peroxide induced double stranded DNA breaks (DSBs) repair in primary neurons. The results showed that the TopoIIβ levels were enhanced during recovery from peroxide mediated damage (PED) along with Ku70, PARP-1, pol beta, and WRN helicase. Furthermore, siRNA mediated knock-down of TopoIIβ in primary neurons conferred enhanced susceptibility to PED in neurons. DSBs in neurons are repaired through two pathways, one promoted by Ku70, while the other is by PARP-1 dependent manner. Participation of TopoIIβ in both pathways was assessed by analysis of the interaction of TopoIIβ with Ku70 and PARP-1 using co-i... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5358346 Mon, 10 Oct 2011 04:00:00 +0100 5358346 http://www.medworm.com/index.php?rid=5342414&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%3D22005392%26dopt%3DAbstract Authors: Fitzpatrick PF Abstract The liver enzyme phenylalanine hydroxylase is responsible for conversion of excess phenylalanine in the diet to tyrosine. Phenylalanine hydroxylase is activated by phenylalanine; this activation is inhibited by the physiological reducing substrate tetrahydrobiopterin. Phosphorylation of Ser16 lowers the concentration of phenylalanine for activation. This review discusses the present understanding of the molecular details of the allosteric regulation of the enzyme. PMID: 22005392 [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=5342414 Fri, 07 Oct 2011 04:00:00 +0100 5342414 http://www.medworm.com/index.php?rid=5342413&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%3D22005393%26dopt%3DAbstract Authors: Fujita H, Kato T, Watanabe N, Takahashi T, Kitagawa S Abstract Calpain inhibitors, including peptide aldehydes (N-acetyl-Leu-Leu-Nle-CHO and N-acetyl-Leu-Leu-Met-CHO) and α-mercapto-acrylic acid derivatives (PD150606 and PD151746), have been shown to stimulate phagocyte functions via activation of human formyl peptide receptor (hFPR) and/or hFPR-like 1 (hFPRL1). Using the homology modeling of the receptors and the ligand docking simulation, here we show that these calpain inhibitors could bind to the putative N-formyl-Met-Leu-Phe (fMLF) binding site on hFPR and/or hFPRL1. The studies with HEK-293 cells stably expressing hFPR or hFPRL1 showed that the concentrations of calpain inhibitors required to induce an increase in cytoplasmic free Ca(2+) ([Ca(2+)](i)) was much highe... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5342413 Fri, 07 Oct 2011 04:00:00 +0100 5342413 http://www.medworm.com/index.php?rid=5342412&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%3D22008468%26dopt%3DAbstract Authors: McAlister-Henn L Abstract Yeast NAD(+)-specific isocitrate dehydrogenase (IDH) is an octameric enzyme composed of four each of regulatory IDH1 and catalytic IDH2 subunits that share 42% sequence identity. IDH2 contains catalytic isocitrate/Mg(2+) and NAD(+) binding sites whereas IDH1 contains homologous binding sites, respectively, for cooperative binding of isocitrate and for allosteric binding of AMP. Ligand binding is highly ordered in vitro, and IDH exhibits the unusual property of half-site binding for all ligands. The structures of IDH solved in the absence or presence of ligands have shown: (a) a heterodimer to be the basic structural/functional unit of the enzyme, (b) the organization of heterodimers to form tetramer and octamer structures, (c) structural differenc... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5342412 Fri, 07 Oct 2011 04:00:00 +0100 5342412 http://www.medworm.com/index.php?rid=5342411&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%3D22008469%26dopt%3DAbstract Authors: Demay MB Abstract The Vitamin D receptor (VDR) plays a critical role in epidermal homeostasis. The ligand-dependent actions of the VDR attenuate epidermal keratinocyte proliferation and promote keratinocyte differentiation. Calcium can compensate for the absence of the VDR in maintaining a normal program of epidermal keratinocyte differentiation both in vitro and in vivo. In contrast, the effects of VDR ablation on the hair follicle cannot be prevented by maintaining normal calcium levels and are independent of 1,25-dihydroxyvitamin D. These actions of the VDR are critical in the keratinocyte stem cell population that resides in the bulge region of the hair follicle. Absence of a functional VDR leads to a self-renewal and lineage progression defect in this population of st... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5342411 Fri, 07 Oct 2011 04:00:00 +0100 5342411 http://www.medworm.com/index.php?rid=5342417&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%3D22001737%26dopt%3DAbstract Authors: L'abbée JB, Tu Y, Barriault D, Sylvestre M Abstract In this work we have investigated the ability of the biphenyl dioxygenase of Burkholderia xenovorans LB400 (BphAE(LB400)) and of Pandoraea pnomenusa B356 (BphAE(B356)) to metabolize DDT. Data show BphAE(LB400) is unable to metabolize this substrate but BphAE(B356) metabolizes DDT to produce two stereoisomers. Structural analysis of DDT-docked BphAE(LB400) and BphAE(B356) identified residue Phe336 of BphAE(LB400) as critical to prevent productive binding of DDT to BphAE(LB400). Furthermore, the fact that residue Gly319 of BphAE(B356) is less constrained than Gly321 of BphAE(LB400) most likely contributes to the ability of BphAE(B356) to bind DDT productively. This was confirmed by examining the ability of BphAE chimeras o... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5342417 Thu, 06 Oct 2011 04:00:00 +0100 5342417 http://www.medworm.com/index.php?rid=5342416&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%3D22001738%26dopt%3DAbstract We report a new ACV analogue δ-(l-α-aminoadipoyl)-l-cysteinyl-d-methionine (ACM), which incorporates a thioether in place of the valinyl sidechain. ACM has been synthesized using solution phase methods and crystallized with IPNS. A crystal structure has been elucidated for the IPNS:Fe(II):ACM complex at 1.44Å resolution. This structure reveals that ACM binds in the IPNS active site such that the sulfur atom of the methionine thioether binds to iron in the oxygen binding site at a distance of 2.57Å. The sulfur of the cysteinyl thiolate sits 2.36Å from the metal. PMID: 22001738 [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=5342416 Thu, 06 Oct 2011 04:00:00 +0100 5342416 http://www.medworm.com/index.php?rid=5342415&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%3D22001739%26dopt%3DAbstract Authors: Francoleon NE, Carrington SJ, Fukuto JM Abstract Hydrogen sulfide is an endogenously generated molecule with many reported physiological functions. Although several biological targets have been proposed, the biochemical mechanisms by which it elicits activity are not established. Thus, in an effort to begin to delineate the fundamental biological chemistry of H(2)S, we have examined the reaction of H(2)S with oxidized thiols and thiol proteins in order to determine whether persulfide formation occurs, is stable and how this may affect protein function. We have found that persulfides are easily generated, relatively stable and can alter enzyme activity. Moreover, we have begun to develop methodology for in situ generation of persulfides to facilitate further study of this p... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5342415 Thu, 06 Oct 2011 04:00:00 +0100 5342415 http://www.medworm.com/index.php?rid=5342419&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%3D22001224%26dopt%3DAbstract Authors: Mikulski R, Domsic JF, Ling G, Tu C, Robbins AH, Silverman DN, McKenna R Abstract The tryptophan residue Trp5, highly conserved in the α class of carbonic anhydrases including human carbonic anhydrase II (HCA II), is positioned at the entrance of the active site cavity and forms a π-stacking interaction with the imidazole ring of the proton shuttle His64 in its outward orientation. We have observed that replacement of Trp5 in HCA II caused significant structural changes, as determined by X-ray diffraction, in the conformation of 11 residues at the N-terminus and in the orientation of the proton shuttle residue His64. Most significantly, two variants W5H and W5E HCA II had His64 predominantly outward in orientation, while W5F and wild type showed the superposition of both... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5342419 Wed, 05 Oct 2011 04:00:00 +0100 5342419 http://www.medworm.com/index.php?rid=5342418&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%3D22001225%26dopt%3DAbstract Authors: Zhang M, Zhou Y, Li T, Wang H, Cheng F, Zhou Y, Bi L, Zhang XE Abstract Different DNA repair systems are known to cooperate to deal with DNA damage. However, the regulatory role of the cross-talk between these pathways is unclear. Here, we have shown that MutL, an essential component of mismatch repair, is a RecA-interacting protein, and that its highly conserved N-terminal domain is sufficient for this interaction. Surface plasmon resonance and capillary electrophoresis analyses revealed that MutL has little effect on RecA-ssDNA filament formation, but dose down-regulate the ATPase activity of RecA. Our findings identify a new role for MutL, and suggest its regulatory role in homologous recombination. PMID: 22001225 [PubMed - as supplied by publisher] (Source: Archive... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5342418 Wed, 05 Oct 2011 04:00:00 +0100 5342418 http://www.medworm.com/index.php?rid=5342420&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%3D21995946%26dopt%3DAbstract Authors: Naletova IN, Popova KM, Eldarov MA, Kuravsky ML, Schmalhausen EV, Sevostyanova IA, Muronetz VI Abstract The cytosolic chaperonin TRiC was isolated from ovine testes using ultracentrifugation and heparin-Sepharose chromatography. The molecular mass of the obtained preparation was shown to exceed 900kDa (by Blue Native PAGE). SDS-PAGE yielded a set of bands in the range of 50-60kDa. Electron microscopy examination revealed ring-shaped complexes with the outer diameter of 15nm and the inner diameter of approximately 6nm. The results suggest that the purified chaperonin is an oligomeric complex composed of two 8-membered rings. The chaperonin TRiC was shown to assist an ATP-dependent refolding of recombinant forms of sperm-specific glyceraldehyde-3-phosphate dehydrogenase, an ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5342420 Mon, 03 Oct 2011 04:00:00 +0100 5342420 http://www.medworm.com/index.php?rid=5342422&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%3D21982919%26dopt%3DAbstract Authors: Wilder CL, Park KY, Keegan PM, Platt MO Abstract Cathepsins K, L, S, and V are cysteine proteases that have been implicated in tissue-destructive diseases such as atherosclerosis, tumor metastasis, and osteoporosis. Among these four cathepsins are the most powerful human collagenases and elastases, and they share 60% sequence homology. Proper quantification of mature, active cathepsins has been confounded by inhibitor and reporter substrate cross-reactivity, but is necessary to develop properly dosed therapeutic applications. Here, we detail a method of multiplex cathepsin zymography to detect and distinguish the activity of mature cathepsins K, L, S, and V by exploiting differences in individual cathepsin substrate preferences, pH effects, and electrophoretic mobility und... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5342422 Thu, 29 Sep 2011 04:00:00 +0100 5342422 http://www.medworm.com/index.php?rid=5342421&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%3D21982920%26dopt%3DAbstract Authors: Karsten WE, Reyes ZL, Bobyk KD, Cook PF, Chooback L Abstract The amino acid l-lysine is synthesized in Saccharomyces cerevisiae via the α-aminoadipate pathway. An as yet unidentified PLP-containing aminotransferase is thought to catalyze the formation of α-aminoadipate from α-ketoadipate in the l-lysine biosynthetic pathway that could be the yeast Aro8 gene product. A screen of several different amino acids and keto-acids showed that the enzyme uses l-tyrosine, l-phenylalanine, α-ketoadipate, and l-α-aminoadipate as substrates. The UV-visible spectrum of the aminotransferase exhibits maxima at 280 and 343nm at pH 7.5. As the pH is decreased the peak at 343nm (the unprotonated internal aldimine) disappears and two new peaks at 328 and 400nm are observed representing th... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5342421 Thu, 29 Sep 2011 04:00:00 +0100 5342421 http://www.medworm.com/index.php?rid=5294325&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%3D21964540%26dopt%3DAbstract Authors: González-Sánchez MI, García-Carmona F, Macià H, Valero E Abstract Hydrogen peroxide triggers a redox cycle between methemoglobin and ferrylhemoglobin, leading to protein inactivation and oxygen evolution. In the present paper, the catalase-like oxygen production by human methemoglobin in the presence of H(2)O(2) was kinetically characterized with a Clark-type electrode. Progress curves showed a pseudo-steady state in the first minutes of the reaction, while double-reciprocal plots were upwardly concave, indicating positive co-operativity dependent upon protein concentration, which is a very unusual kinetic behavior. Addition of superoxide radical scavengers slightly increased activity, suggesting that most oxygen was produced biocatalytically. By considering all the ex... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5294325 Thu, 22 Sep 2011 04:00:00 +0100 5294325 http://www.medworm.com/index.php?rid=5294324&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%3D21967851%26dopt%3DAbstract Authors: Stampler J, Bellei M, Soudi M, Gruber C, Battistuzzi G, Furtmüller PG, Obinger C Abstract In mammalian peroxidases the proximal histidine is in close interaction with a fully conserved asparagine which in turn is hydrogen bonded with an arginine that stabilizes the propionate substituent of pyrrol ring D in bent conformation. In order to probe the role of this rigid proximal architecture for structural integrity and catalysis of human myeloperoxidase (MPO), the variants Asn421Asp, Arg333Ala and Arg333Lys have been recombinantly expressed in HEK cell lines. The standard reduction potential of the Fe(III)/Fe(II) couple of Asn421Asp was still wild-type-like (-50mV at pH 7.0) but the spectral properties of the ferric and ferrous forms as well as of higher oxidation states sho... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5294324 Thu, 22 Sep 2011 04:00:00 +0100 5294324 http://www.medworm.com/index.php?rid=5294323&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%3D21967852%26dopt%3DAbstract Authors: Flores AM, Gurevich I, Zhang C, Ramirez VP, Devens TR, Aneskievich BJ Abstract Nuclear receptor (NR) coregulators include coactivators, contributing to holoreceptor transcriptional activity, and corepressors, mediating NR target gene silencing in the absence of hormone. We identified an atypical NR coregulator, TNFα-induced protein 3-interacting protein 1 (TNIP1), from a peroxisome proliferator activated receptor (PPAR) α screen of a human keratinocyte cDNA library. TNIP1's complex nomenclature parallels its additional function as an NF-κB inhibitor. Here we show TNIP1 is an atypical NR corepressor using two-hybrid systems, biochemical studies, and receptor activity assays. The requirements for TNIP1-PPAR interaction are characteristic for coactivators; however, TNIP1 p... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5294323 Thu, 22 Sep 2011 04:00:00 +0100 5294323 http://www.medworm.com/index.php?rid=5294326&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%3D21964243%26dopt%3DAbstract Authors: Sinha RK, Patel RY, Bojjireddy N, Datta A, Subrahmanyam G Abstract Type II phosphatidylinositol (PtdIns) 4-kinases produce PtdIns 4-phosphate, an early key signaling molecule in phosphatidylinositol cycle, which is indispensable for T cell activation. Type II PtdIns 4-kinase alpha and beta have similar biochemical properties. To distinguish these isoforms Epigallocatechin gallate (EGCG) has been evaluated as a specific inhibitor. EGCG is the major active catechin in green tea having anti-inflammatory, antiatherogenic and cancer chemopreventive properties. The precise mechanism of actions and molecular targets of EGCG in early signaling cascades are not well understood. In the present study, we have shown that EGCG inhibits type II PtdIns 4-kinases (α and β isoforms) and ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5294326 Wed, 21 Sep 2011 04:00:00 +0100 5294326 http://www.medworm.com/index.php?rid=5273717&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%3D21951814%26dopt%3DAbstract Authors: Walther M, Hofheinz K, Vogel R, Roffeis J, Kühn H Abstract Mammalian lipoxygenases (LOXs) have been implicated in cell differentiation and in the pathogenesis of inflammatory and hyperproliferative diseases. The available structural information indicated that lipoxygenases constitute single polypeptide chain enzymes consisting of a small N-terminal β-barrel domain and a larger C-terminal subunit that harbors the catalytic non-heme iron. Because of its structural similarity to C2-domains of lipases the N-terminal β-barrel domain of lipoxygenases, which comprises about 110 amino acids, has been implicated in membrane binding and activity regulation. To explore the functional relevance of the C2-domain in more detail and to develop a more comprehensive hypothesis on the bi... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5273717 Sat, 17 Sep 2011 04:00:00 +0100 5273717 http://www.medworm.com/index.php?rid=5273713&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%3D21951815%26dopt%3DAbstract Authors: Luo J, Gräslund A Abstract Ribonucleotide reductase (RNR) is necessary for production of the precursor deoxyribonucleotides for DNA synthesis. Class Ia RNR functions via a stable free radical in one of the two components protein R2. The enzyme mechanism involves long range (proton coupled) electron transfer between protein R1 and the tyrosyl radical in protein R2. Earlier experimental studies showed that p-alkoxyphenols inhibit RNR. Here, molecular docking and molecular dynamics simulations involving protein R2 suggest an inhibition mechanism for p-alkoxyphenols . A low energy binding pocket is identified in protein R2. The preferred configuration provides a structural basis explaining their specific binding to the Escherichia coli and mouse R2 proteins. Trp48 (E. coli nu... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5273713 Sat, 17 Sep 2011 04:00:00 +0100 5273713 http://www.medworm.com/index.php?rid=5241447&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%3D21933660%26dopt%3DAbstract Authors: Morotomi-Yano K, Akiyama H, Yano KI Abstract Application of nanosecond pulsed electric fields (nsPEFs) has attracted attention as a unique tool in life sciences, especially for cancer therapy, but the molecular mechanism of its action on living organisms is yet to be fully elucidated. Here, we report a transient activation of signaling pathways involving mitogen-activated protein kinases (MAPKs) by nsPEFs. Application of nsPEFs to HeLa S3 cells induced phosphorylation of MAPKs, including p38, JNK and ERK, and their upstream kinases. The application of nsPEFs also elicited elevated phosphorylation of downstream factors including MSK1, Hsp27, ATF2, p90RSK, and c-Jun. In addition, the application of nsPEFs led to the transcriptional activation of immediate early genes in the ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5241447 Sat, 10 Sep 2011 04:00:00 +0100 5241447 http://www.medworm.com/index.php?rid=5241446&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%3D21933661%26dopt%3DAbstract Authors: Zanatta L, Zamoner A, Gonçalves R, Zanatta AP, Bouraïma-Lelong H, Bois C, Carreau S, Silva FR Abstract 1α,25-Dihydroxyvitamin D(3) (1,25D(3)) is critical for the maintenance of normal reproduction since reduced fertility is observed in vitamin D-deficient male rats. The aim of this study was to investigate the effect of 1,25D(3) in 30-day-old rat testicular plasma membrane targets (calcium uptake and gamma-glutamyl transpeptidase (GGTP) activity), as well as to highlight the role of protein kinases in the mechanism of action of 1,25D(3). The results demonstrated that 1,25D(3) induced a fast increase in calcium uptake in rat testis through a nongenomic mechanism of action. This effect was dependent on PKA, PKC and MEK. Moreover, ionic channels, such as ATP- and Ca(2+)-de... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5241446 Sat, 10 Sep 2011 04:00:00 +0100 5241446 http://www.medworm.com/index.php?rid=5241461&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%3D21924233%26dopt%3DAbstract Authors: Cianciola NL, Carlin CR, Kelley TJ Abstract It has been less than two decades since the underlying genetic defects in Niemann-Pick disease Type C were first identified. These defects impair function of two proteins with a direct role in lipid trafficking, resulting in deposition of free cholesterol within late endosomal compartments and a multitude of effects on cell function and clinical manifestations. The rapid pace of research in this area has vastly improved our overall understanding of intracellular cholesterol homeostasis. Excessive cholesterol buildup has also been implicated in clinical manifestations associated with a number of genetically unrelated diseases including cystic fibrosis. Applying knowledge about anomalous cell signaling behavior in cystic fibrosis o... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5241461 Mon, 05 Sep 2011 04:00:00 +0100 5241461 http://www.medworm.com/index.php?rid=5241454&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%3D21924234%26dopt%3DAbstract Authors: Zhang Z, Feng HZ, Jin JP Abstract We previously reported that the NH(2)-terminal variable region of cardiac troponin T (cTnT) is removed by restrictive μ-calpain cleavage in myocardial ischemia-reperfusion [24]. Selective removal of the NH(2)-terminal variable region of cTnT had a compensatory effect on myocardial contractility [25]. Here we further studied this posttranslational modification under pathophysiological conditions. Thrombin perfusion of isolated mouse hearts and cardiomyocytes induced the production of NH(2)-terminal truncated cTnT (cTnT-ND), suggesting a role of calcium overloading. Ouabain treatment of primary cultures of mouse cardiomyocytes in hypokalemic media, another calcium overloading condition, also produced cTnT-ND. Exploring the molecular mechani... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5241454 Mon, 05 Sep 2011 04:00:00 +0100 5241454 http://www.medworm.com/index.php?rid=5215902&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%3D21896270%26dopt%3DAbstract Authors: Rosenbaum E, Gabel F, Durá MA, Finet S, Cléry-Barraud C, Masson P, Franzetti B Abstract While molecular adaptation to high temperature has been extensively studied, the effect of hydrostatic pressure on protein structure and enzymatic activity is still poorly understood. We have studied the influence of pressure on both the quaternary structure and enzymatic activity of the dodecameric TET3 peptidase from Pyrococcus horikoshii. Small angle X-ray scattering (SAXS) revealed a high robustness of the oligomer under high pressure of up to 300MPa at 25°C as well as at 90°C. The enzymatic activity of TET3 was enhanced by pressure up to 180MPa. From the pressure behavior of the different rate-constants we have determined the volume changes associated with substrate binding and... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5215902 Sat, 03 Sep 2011 04:00:00 +0100 5215902 http://www.medworm.com/index.php?rid=5215898&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%3D21907701%26dopt%3DAbstract Authors: Irving AA, Halberg RB, Albrecht DM, Plum LA, Krentz KJ, Clipson L, Drinkwater N, Amos-Landgraf JM, Dove WF, Deluca HF Abstract Epidemiological studies indicate that sunlight exposure and vitamin D are each associated with a lower risk of colon cancer. The few controlled supplementation trials testing vitamin D in humans reported to date show conflicting results. We have used two genetic models of familial colon cancer, the Apc(Pirc/+) (Pirc) rat and the Apc(Min/+) (Min) mouse, to investigate the effect of 25-hydroxyvitamin D(3) [25(OH)D(3)] and two analogs of vitamin D hormone on colonic tumors. Longitudinal endoscopic monitoring allowed us to test the efficacy of these compounds in preventing newly arising colonic tumors and in affecting established colonic tumors. 25(OH)... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5215898 Thu, 01 Sep 2011 04:00:00 +0100 5215898 http://www.medworm.com/index.php?rid=5215901&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%3D21906582%26dopt%3DAbstract This study evaluated the anticancer activity of phenyl-2-aminoethyl selenide (PAESe) and its potential to reduce doxorubicin (DOX)-induced cardiotoxicity. Growth inhibitory effects of PAESe with DOX, and vincristine, clinically used anticancer agents, and tert-butylhydroperoxide (TBHP), a known oxidant, on the growth of human prostate carcinoma (PC-3) cells was determined. PAESe (⩽1μm) did not alter the growth of PC-3 cells, however, concomitant use of PAESe decreased the oxidative-mediated cytotoxicity of TBHP, but had limited effect on vincristine or DOX activity. Further, PAESe decreased the formation of intracellular reactive oxygen species from TBHP and DOX. The effect of PAESe on the activity of DOX was determined using a tumor (PC-3) xenograft model in mice. PAESe did not alter D... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5215901 Wed, 31 Aug 2011 04:00:00 +0100 5215901 http://www.medworm.com/index.php?rid=5215900&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%3D21907178%26dopt%3DAbstract In this study, rat VKORC1 and its most frequent mutants L120Q-, L128Q-, Y139C-, Y139S- and Y139F-VKORC1 were expressed as membrane-bound proteins in Pichia pastoris and characterized by the determination of kinetic and inhibition parameters. The recombinant rVKORC1 showed similar properties than those of the native proteins expressed in the rat liver microsomes, validating the expression system as a good model to study the consequences of VKORC1 mutations. The determination of the inhibition parameters towards various antivitamin K anticoagulants demonstrated that mutations at Leu-120, Leu-128 and Tyr-139 confer the resistance to the first generation AVKs observed in wild rat populations. PMID: 21907178 [PubMed - as supplied by publisher] (Source: Archives of Biochemistry and Biophysic... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5215900 Wed, 31 Aug 2011 04:00:00 +0100 5215900 http://www.medworm.com/index.php?rid=5215899&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%3D21907179%26dopt%3DAbstract Authors: Matias A, Marinho HS, Cyrne L, Herrero E, Antunes F Abstract Taking into account published contradictory results concerning the regulation of fatty acid synthase (Fas) by H(2)O(2), we carried out a systematic study where two methods of H(2)O(2) delivery (steady-state and bolus addition) and the effect of a wide range of H(2)O(2) concentrations were investigated. A decrease in Fas activity was observed for cells exposed to 100 and 150μM H(2)O(2) in a steady-state, while a bolus addition of the same H(2)O(2) concentrations did not alter Fas activity. Similar results were observed for the mRNA levels of FAS1, the gene that encodes Fas subunit β. However, the exposure to a steady-state 50μM H(2)O(2) dose lead to an increase in FAS1 mRNA levels, showing a biphasic modulation... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5215899 Wed, 31 Aug 2011 04:00:00 +0100 5215899 http://www.medworm.com/index.php?rid=5215903&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%3D21893024%26dopt%3DAbstract Authors: Yadav RK, Pal S, Dolai S, Adak S Abstract The active site architecture of Leishmania major peroxidase (LmP) is very similar with both cytochrome c peroxidase and ascorbate peroxidase. We utilized point mutagenesis to investigate if the conserved proximal methionine residues (Met248 and Met249) in LmP help in controlling catalysis. Steady-state kinetics of methionine mutants shows that ferrocytochrome c oxidation is <2% of wild type levels without affecting the second order rate constant of first phase of Compound I formation, while the activity toward a small molecule substrate, guaiacol or iodide, increases. Our diode array stopped-flow spectral studies show that the porphyrin π-cation radical of Compound I in mutant LmP is more stable than wild type enzyme. These res... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5215903 Sat, 27 Aug 2011 04:00:00 +0100 5215903 http://www.medworm.com/index.php?rid=5215904&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%3D21889487%26dopt%3DAbstract Authors: Xu S, Little PJ, Lan T, Huang Y, Le K, Wu X, Shen X, Huang H, Cai Y, Tang F, Wang H, Liu P Abstract Tanshinone II-A (Tan), a bioactive diterpene isolated from Salvia miltiorrhiza Bunge (Danshen), possesses anti-oxidant and anti-inflammatory activities. The present study investigated whether Tan can decrease and stabilize atherosclerotic plaques in Apolipoprotein-E knockout (ApoE(-/-)) mice maintained on a high cholesterol diet (HCD). Six week-old mice challenged with a HCD were randomly assigned to 4 groups: (a) C57BL/6J; (b) ApoE(-/-); (c) ApoE(-/-)+Tan-30 (30mg/kg/d); (d) ApoE(-/-)+Tan-10 (10mg/kg/d). After 16weeks of intervention, Tan treated mice showed decreased atherosclerotic lesion size in the aortic sinus and en face aorta. Furthermore, immunohistochemical analysi... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5215904 Fri, 26 Aug 2011 04:00:00 +0100 5215904 http://www.medworm.com/index.php?rid=5189881&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%3D21878319%26dopt%3DAbstract Authors: Xu XL, Chen S, Grant GA Abstract A structural database search has revealed that the same fold found in the allosteric substrate binding (ASB) domain of Mycobacterium tuberculosis D-3-phosphoglycerate dehydrogenase (PGDH) is found in l-serine dehydratase from Legionella pneumophila. The M. tuberculosis PGDH ASB domain functions in the control of catalytic activity. Bacterial l-serine dehydratases are 4Fe-4S proteins that convert l-serine to pyruvate and ammonia. Sequence homology reveals two types depending on whether their α and β domains are on the same (Type 2) or separate (Type 1) polypeptides. The α domains contain the catalytic iron-sulfur center while the β domains do not yet have a described function, but the structural homology with PGDH suggests a regulatory r... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5189881 Mon, 22 Aug 2011 23:00:00 +0100 5189881 http://www.medworm.com/index.php?rid=5171658&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%3D21864499%26dopt%3DAbstract Authors: Gutiérrez A, Babot ED, Ullrich R, Hofrichter M, Martínez AT, Del Río JC Abstract Reaction of fatty acids, fatty alcohols, alkanes, sterols, sterol esters and triglycerides with the so-called aromatic peroxygenase from Agrocybe aegerita was investigated using GC-MS. Regioselective hydroxylation of C(12)-C(20) saturated/unsaturated fatty acids was observed at the ω-1 and ω-2 positions (except myristoleic acid only forming the ω-2 derivative). Minor hydroxylation at ω and ω-3 to ω-5 positions was also observed. Further oxidized products were detected, including keto, dihydroxylated, keto-hydroxy and dicarboxylic fatty acids. Fatty alcohols also yielded hydroxy or keto derivatives of the corresponding fatty acid. Finally, alkanes gave, in addition to alcohols at posit... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5171658 Mon, 15 Aug 2011 23:00:00 +0100 5171658 http://www.medworm.com/index.php?rid=5171653&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%3D21864500%26dopt%3DAbstract Authors: Zucchini D, Caprini G, Pasterkamp RJ, Tedeschi G, Vanoni MA Abstract MICALs form a conserved multidomain protein family essential for cytoskeletal rearrangements. To complement structural information available, we produced the FAD-containing monooxygenase-like domain of human MICAL-1 (MICAL-MO) in forms differing for the presence and location of a His-tag, which only influences the protein yields. The K(m) for NADPH of the NADPH oxidase reaction is sensitive to ionic strength and type of ions. The apparent k(cat) (pH 7) is limited by enzyme reduction by NADPH, which occurs without detectable intermediates, as established by anaerobic rapid reaction experiments. The sensitivity to ionic strength and type of ions and the pH dependence of the steady-state kinetic parameters e... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5171653 Mon, 15 Aug 2011 23:00:00 +0100 5171653 http://www.medworm.com/index.php?rid=5171651&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%3D21867675%26dopt%3DAbstract In this report, we examine the effects of phosphoenolpyruvate (PEP), a glycolytic intermediate, on mitochondrial function. It is reported here that in rat heart mitochondria, PEP delays the onset of state 3 respiration in mitochondria supplied with either NADH-linked substrates or succinate. However, the maximal rate of state 3 respiration is only inhibited when oxidative phosphorylation is supported by NADH-linked substrates. The capacity of PEP to delay and/or inhibit state 3 respiration is dependent upon the presence or absence of ATP. Inhibition of state 3 is exacerbated in uncoupled mitochondria, with a 40% decrease in respiration seen with 0.1mM PEP. In contrast, ATP added exogenously or produced by oxidative phosphorylation completely prevents PEP-mediated inhibition. Mechanisticall... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5171651 Mon, 15 Aug 2011 23:00:00 +0100 5171651 http://www.medworm.com/index.php?rid=5171650&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%3D21867676%26dopt%3DAbstract Authors: Yokoyama Y, Iguchi K, Usui S, Hirano K Abstract Aquaporin 9 (AQP9) is permeable to glycerol, which is a source material in lipogenesis and gluconeogenesis in the liver. We investigated the transcriptional regulation of the AQP9 gene by AMP-activated protein kinase (AMPK), known as an energy sensor in cells since AMPK contributes to the metabolism of carbohydrate, lipid, and protein by regulating the expression of many enzymes and transcription factors in metabolic pathways. An AMPK activator, 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR), was observed to suppress the expression of the AQP9 gene in HepG2 cells by promoting the phosphorylation of AMPK and AKT/PKB. Forkhead box a2 (Foxa2) was speculated to be one of the transcriptional regulators of AQP9 gene e... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5171650 Mon, 15 Aug 2011 23:00:00 +0100 5171650 http://www.medworm.com/index.php?rid=5139408&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%3D21840294%26dopt%3DAbstract Authors: Arvadia P, Narwaley M, Whittal RM, Siraki AG Abstract Inhibition of human peroxidase enzymes such as myeloperoxidase or eosinophil peroxidase represents a novel therapeutic area, for which there are no current clinical therapeutics. We utilized 4-aminobenzoic acid hydrazide which was reported to be a potent irreversible inhibitor of myeloperoxidase to gain insight into the role of reactive metabolites in catalytic inhibition. In order to carry out detailed studies, we used a model peroxidase, microperoxidase-11 (MP-11). We investigated the heme spectrum of MP-11 in the presence of 4-ABAH and found that heme bleaching occurred that was irreversible. This coincided with an absence of catalytic activity. The spin trap 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) was able to signif... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5139408 Mon, 08 Aug 2011 23:00:00 +0100 5139408 http://www.medworm.com/index.php?rid=5139407&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%3D21843498%26dopt%3DAbstract Authors: McDonough RT, Paranjape G, Gallazzi F, Nichols MR Abstract Amyloid-β protein (Aβ) is the principal component of the neuritic plaques found in Alzheimer's disease. The predominant Aβ morphology in the plaques is fibrillar which has prompted substantial in vitro work to better understand the molecular organization of Aβ fibrils. In the current study, tryptophan substitutions were made at Aβ(1-40) position 19 (F19W) or 20 (F20W) to ascertain environmental differences between the two residues in the fibril structure. Kinetic studies revealed similar rates of fibril formation between Aβ(1-40) F19W and F20W and both peptides formed typical amyloid fibril structures. Aβ(1-40) F19W fibrils displayed a significant tryptophan fluorescence blue-shift in λ(max) (33nm) compared... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5139407 Fri, 05 Aug 2011 23:00:00 +0100 5139407 http://www.medworm.com/index.php?rid=5139406&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%3D21843499%26dopt%3DAbstract This study provides the Daxx trafficking as a new potential therapeutic target for ischemic brain injury. PMID: 21843499 [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=5139406 Fri, 05 Aug 2011 23:00:00 +0100 5139406 http://www.medworm.com/index.php?rid=5139405&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%3D21843500%26dopt%3DAbstract In this study, we investigated productions of superoxide anions (O(2)(-)) and nitric oxide (NO), and apoptotic cell death in wild type Chinese hamster ovary (CHO) cells and cholesterol accumulated CHO cells genetically and chemically. Oxidative stress was induced by menadione challenge. The results revealed that abundance of free cholesterol (FC) promoted menadione-induced O(2)(-) and NO productions. FC accumulation down-regulated eNOS expression but up-regulated NADPH oxidases, and inhibited the activities of superoxide dismutase (SOD) and catalase. Treatment of menadione increased the expressions of iNOS and qp91 phox, enhanced the activities of SOD and catalase in the wild-type CHO cells but inhibited the activity of glutathione peroxidase in the cholesterol accumulated CHO cells. Moreo... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5139405 Fri, 05 Aug 2011 23:00:00 +0100 5139405 http://www.medworm.com/index.php?rid=5139409&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%3D21820400%26dopt%3DAbstract This study provides first direct evidence of DDO presence in human tissue proteins and establishes that AGE crosslink synthesis in the human lens occurs via DDO intermediates. PMID: 21820400 [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=5139409 Wed, 27 Jul 2011 23:00:00 +0100 5139409 http://www.medworm.com/index.php?rid=5139410&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%3D21819960%26dopt%3DAbstract Authors: Ekanayake DK, West AH, Cook PF Abstract Saccharopine dehydrogenase catalyzes the NAD-dependent oxidative deamination of saccharopine to l-lysine and α-ketoglutarate. Lysine 99 is within hydrogen-bond distance to the α-carboxylate of the lysine substrate and D319 is in the vicinity of the carboxamide side chain of NADH. Both are conserved and may be important to the overall reaction. Replacing K99 with M gives decreases of 110-, 80- and 20-fold in the V(2)/K(m) values for lysine, α-ketoglutarate and NADH, respectively. Deuterium isotope effects on V and V/K(Lys) increase, while the solvent deuterium isotope effects decrease compared to the C205S mutant enzyme. Data for K99M suggest a decreased affinity for all reactants and a change in the partition ratio of the imine in... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5139410 Tue, 26 Jul 2011 23:00:00 +0100 5139410 http://www.medworm.com/index.php?rid=5092117&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%3D21798231%26dopt%3DAbstract Authors: Bobyk KD, Kim SG, Kumar VP, Kim SK, West AH, Cook PF Saccharopine dehydrogenase catalyzes the NAD-dependent conversion of saccharopine to generate l-lysine and α-ketoglutarate. A disulfide bond between cysteine 205 and cysteine 249, in the vicinity of the dinucleotide-binding site, is observed in structures of the apoenzyme, while a dithiol is observed in a structure with AMP bound, suggesting preferential binding of the dinucleotide to reduced enzyme. Mutation of C205 to S gave increased values of V/E(t) and V/KE(t) at pH 7 compared to wild type. Primary deuterium and solvent deuterium kinetic isotope effects suggest the catalytic pathway, which includes the hydride transfer and hydrolysis steps, contributes more to rate limitation in C205S, but the rates of the two steps re... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5092117 Sun, 24 Jul 2011 23:00:00 +0100 5092117 http://www.medworm.com/index.php?rid=5092116&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%3D21802402%26dopt%3DAbstract This study indicates that reduced extracellular calcium concentrations up-regulate TRPC3 channel protein expression in patients with chronic kidney disease. PMID: 21802402 [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=5092116 Fri, 22 Jul 2011 23:00:00 +0100 5092116 http://www.medworm.com/index.php?rid=5092115&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%3D21802403%26dopt%3DAbstract Authors: Vashchenko G, Bleackley MR, Griffiths TA, Macgillivray RT Hephaestin is a multicopper ferroxidase involved in iron absorption in the small intestine. Expressed mainly on the basolateral surface of duodenal enterocytes, hephaestin facilitates the export of iron from the intestinal epithelium into blood by oxidizing Fe(2+) into Fe(3+), the only form of iron bound by the plasma protein transferrin. Structurally, the human hephaestin ectodomain is predicted to resemble ceruloplasmin, the major multicopper oxidase in blood. In addition to its ferroxidase activity, ceruloplasmin was reported to oxidize a wide range of organic compounds including a group of physiologically relevant substrates (biogenic amines). To study oxidation of organic substrates, the human hephaestin ectodomain... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5092115 Fri, 22 Jul 2011 23:00:00 +0100 5092115 http://www.medworm.com/index.php?rid=5092144&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%3D21784055%26dopt%3DAbstract Authors: Masuda W, Jimi E CD38 is a 42-45kDa transmembrane glycoprotein that exhibits ADP-ribosyl cyclase enzyme activity. In the rat, we have previously reported strong ADP-ribosyl cyclase activity in the sublingual salivary gland (Masuda W. and Noguchi T. Biochem. Biophys. Res. Commun. (2000) 270, 469-472). Here, we have examined the specific localization of CD38/ADP-ribosyl cyclase activity in this gland and whether that localization changes upon saliva-secretary stimulation. Under resting conditions, CD38/ADP-ribosyl cyclase activity in the post-nuclear fraction of SLG homogenates was separated into two major peaks by sucrose density gradient centrifugation. The first peak included the plasma membrane proteins Na(+)/K(+) ATPase and aquaporin 5, while the second peak included mucous... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5092144 Mon, 18 Jul 2011 23:00:00 +0100 5092144 http://www.medworm.com/index.php?rid=5092132&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%3D21784056%26dopt%3DAbstract Authors: Deluca HF, Plum LA Multiple sclerosis incidence is clearly inversely related to sun exposure. This observation led to the idea that vitamin D might be responsible for this relationship. Providing super-physiologic doses of the hormonal form of vitamin D, 1α,25-dihydroxyvitamin D(3), suppresses an animal model of multiple sclerosis, i.e. experimental autoimmune encephalomyelitis (EAE) but causes unwanted hypercalcemia. Further, dietary calcium is needed for this activity of 1α,25-dihydroxyvitamin D(3). B10PL mice were maintained on a vitamin D-deficient diet for two generations to produce frank vitamin D deficiency. These animals showed delayed onset and reduced severity of EAE compared to control animals on the same diet and given vitamin D(3) or provided a vitamin D-contain... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5092132 Mon, 18 Jul 2011 23:00:00 +0100 5092132 http://www.medworm.com/index.php?rid=5092119&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%3D21784057%26dopt%3DAbstract Authors: Chandrashekaran IR, Adda CG, Macraild CA, Anders RF, Norton RS Merozoite surface protein 2 (MSP2), one of the most abundant proteins on the surface of Plasmodium falciparum merozoites, is a promising malaria vaccine candidate. MSP2 is intrinsically unstructured and forms amyloid-like fibrils in solution. As this propensity of MSP2 to form fibrils in solution has the potential to impede its development as a vaccine candidate, finding an inhibitor that inhibits fibrillogenesis may enhance vaccine development. We have shown previously that EGCG inhibits the formation of MSP2 fibrils. Here we show that EGCG can alter the β-sheet-like structure of the fibril and disaggregate pre-formed fibrils of MSP2 into soluble oligomers. The fibril remodelling effects of EGCG and other flavono... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5092119 Mon, 18 Jul 2011 23:00:00 +0100 5092119 http://www.medworm.com/index.php?rid=5092118&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%3D21784058%26dopt%3DAbstract Authors: Wengert M, Adão-Novaes J, Leão-Ferreira LR, Caruso-Neves C There is some evidence to show a possible role of guanosine in the modulation of cellular function, in particular, in the neuronal system. However, nothing is known about the role of guanine in renal function. The aim of the present work was to investigate the role of guanine on modulation of Na(+)-ATPase activity in isolated basolateral membrane (BLM) of the renal cortex. Guanine inhibited the enzyme activity in a dose-dependent manner with maximal effect (56%) obtained at 10(-6)M. This effect was reversed by DPCPX (8-cyclopentyl-1,3-dipropylxanthine), an antagonist of A(1) receptors, but it was not changed by 10(-8)M DMPX (3,7-dimethyl-1-propargylxanthine) or 10(-8)M MRS (2,3-diethyl-4,5-dipropyl-6-phenylpyridine-3... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5092118 Mon, 18 Jul 2011 23:00:00 +0100 5092118 http://www.medworm.com/index.php?rid=5092160&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%3D21782785%26dopt%3DAbstract Authors: Mulrooney SB, Howard MJ, Hausinger RP Microorganisms are exposed to a wide variety of exogenous and endogenous chemical agents that alkylate DNA. Escherichia coli cells exhibit an adaptive response that recognizes and repairs alkylated DNA lesions using Ada, AlkA, and AlkB enzymes. Another alkylation response protein, the DNA-binding flavoprotein AidB, was proposed to repair DNA or protect it from chemical alkylating agents, but direct evidence for its role is lacking. Here, AidB was shown to form tight complexes with both flavodoxin and acyl carrier protein. In addition, electron transfer between 1-electron and 2-electron reduced flavodoxin to oxidized AidB was observed, although with very small rate constants. AidB was found to bind to RNA, raising the prospect that the prot... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5092160 Sun, 17 Jul 2011 23:00:00 +0100 5092160 http://www.medworm.com/index.php?rid=5041199&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%3D21767524%26dopt%3DAbstract Authors: Xiao H, Dee D, Yada RY Plasmepsin II (PMII), an aspartic protease from the malarial parasite Plasmodium falciparum, represents a model for understanding protease structure/function relationships due to its unique structure and properties. The present study undertook a thermodynamic and kinetic analysis of the PMII folding mechanism and a pH stability profile. Differential scanning calorimetry revealed that the native state of PMII (Np) was irreversibly unfolded, and in the pH range of 6.5-8.0, PMII refolds to a denatured state (Rp) with higher thermal stability than Np. Rp could also be formed upon partially unfolding PMII at pH 11.0 and 37°C for 2h, followed by adjustment to a pH in the range of 6.5-8.0. While Rp could be folded/unfolded reversibly, Np was shown to exist as ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5041199 Thu, 14 Jul 2011 23:00:00 +0100 5041199 http://www.medworm.com/index.php?rid=5041198&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%3D21767525%26dopt%3DAbstract Authors: Shemetov AA, Gusev NB Interaction of human Bag3 with small heat shock proteins HspB6, HspB8 and its K141E mutant was analyzed by different biochemical methods. The data of size-exclusion chromatography indicate that the wild type HspB8 forms tight complexes with Bag3. K141E mutant of HspB8 and especially HspB6 weaker interact with Bag3. The data of chemical crosslinking and analytical ultracentrifugation indicate that in vitro the stoichiometry of complexes formed by HspB8 and Bag3 is variable and is dependent on concentration of protein partners. Interaction of Bag3 and HspB8 is accompanied by increase of thermal stability measured by intrinsic tryptophan fluorescence and increased resistance to limited chymotrypsinolysis. The data of size-exclusion chromatography, analytical... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5041198 Thu, 14 Jul 2011 23:00:00 +0100 5041198 http://www.medworm.com/index.php?rid=5041197&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%3D21767526%26dopt%3DAbstract Authors: Davis JA, Greene RJ, Han S, Rock DA, Wienkers LC Raloxifene is a polyaromatic compound which has been reported to form radicals when incubated with horseradish peroxidase resulting in formation of a homo-dimer product. Polyaromatic phenols have also been reported to undergo oxidation by P450 enzymes to form reactive intermediates, presumably through the formation of phenoxy radical species. Recently, we observed that a raloxifene homo-dimer was formed in vitro when incubated with CYP3A4. In response to this finding, a series of experiments were designed to determine whether the observed raloxifene homo-dimer was formed via solution phase chemistry similar to that previously documented with horseradish peroxidase or if generation of the homo-dimer occurred within the P450 activ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5041197 Thu, 14 Jul 2011 23:00:00 +0100 5041197 http://www.medworm.com/index.php?rid=5041196&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%3D21767527%26dopt%3DAbstract Authors: Loumaye E, Ferrer-Sueta G, Alvarez B, Rees JF, Clippe A, Knoops B, Radi R, Trujillo M Arenicola marina lives in marine environments where hydrogen peroxide concentrations reach micromolar levels. The annelid also forms reactive species through metabolic pathways. Its antioxidant systems include a cytosolic peroxiredoxin, peroxiredoxin 6 (AmPrx6 or AmPRDX6) that shows high homology to the mammalian 1-Cys peroxiredoxin. Previous work confirmed the peroxidase activity of AmPrx6 in the presence of dithiotreitol. Herein, we performed an in vitro kinetic characterization of the recombinant enzyme. AmPrx6 reduced hydrogen peroxide and peroxynitrite with rate constants of 1.1×10(7) and 2×10(6)M(-1)s(-1), respectively, at pH 7.4 and 25°C. Reduction of tert-butyl hydroperoxide was sl... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5041196 Thu, 14 Jul 2011 23:00:00 +0100 5041196 http://www.medworm.com/index.php?rid=5041201&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%3D21763267%26dopt%3DAbstract Authors: Katz S, Ayala V, Santillán G, Boland R We studied the PI3K/Akt signaling pathway modulation and its involvement in the stimulation of ROS 17/2.8 osteoblast-like cell proliferation by extracellular ATP. A dose- and time-dependent increase in Akt-Ser 473 phosphorylation (p-Akt) was observed. p-Akt was increased by ATPγS and UTP, but not by ADPβS. Akt activation was abolished by PI3K inhibitors and reduced by inhibitors of PI-PLC, Src, calmodulin (CaM) but not of CaMK. p-Akt was diminished by cell incubation in a Ca(2+)-free medium but not by the use of L-type calcium channel blockers. The rise in intracellular Ca(2+) induced by ATP was potentiated in the presence of Ro318220, a PKC inhibitor, and attenuated by the TPA, a known activator of PKC. ATP-dependent p-Akt was diminis... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5041201 Tue, 05 Jul 2011 23:00:00 +0100 5041201 http://www.medworm.com/index.php?rid=5041200&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%3D21763268%26dopt%3DAbstract In conclusion, the present stereochemical studies revealed high regioselectivity of the Chironomus enzyme to hydroxylate both steroids at the same methyl group, denoted C-27. PMID: 21763268 [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=5041200 Tue, 05 Jul 2011 23:00:00 +0100 5041200 http://www.medworm.com/index.php?rid=5041203&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%3D21741352%26dopt%3DAbstract Authors: Pérez-Lara A, Corbalán-García S, Gómez-Fernández JC Curcumin modulates the activity of protein kinase Cα (PKCα) when assayed in the presence of vesicles including phosphatidylcholine, phosphatidylserine and diacylglycerol. Increasing concentrations of curcumin progressively increased PKCα activity at concentrations lower than 20μM, but at higher concentrations of curcumin the activity decreased although, at concentrations of curcumin of up to 100μM the activity was always higher than the basal one (in the absence of curcumin). The maximum activity was reached at 3μM curcumin, at 20 and 30mol% of phosphatidylserine, 10μM Ca(2+) and 2mol% diacylglycerol. The same type of modulation was observed when changing the concentration of phosphatidylserine, diacylglycerol and... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5041203 Tue, 28 Jun 2011 23:00:00 +0100 5041203 http://www.medworm.com/index.php?rid=5041202&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%3D21741353%26dopt%3DAbstract In conclusion, human POR mutations, shown to impact P450 activities, also result in varying degrees of diminished HO-1 activity, which may further complicate CYPOR deficiency. PMID: 21741353 [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=5041202 Mon, 27 Jun 2011 23:00:00 +0100 5041202 http://www.medworm.com/index.php?rid=5041204&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%3D21723849%26dopt%3DAbstract In this study, we identified compounds produced by the reaction between ChA or CaA in coffee and NaNO(2) in artificial gastric juice. The identified phenolic compounds and nitrated phenolic compounds were assessed for their anti-oxidant, pro-oxidant, and nitration activities by performing an in vitro assay. The nitrated phenolic compounds seemed to show increased anti-oxidant activity and decreased pro-oxidant activity. However, one nitrated CaA compound that has a furoxan ring showed the ability to release NO(2)(-) in the neutral condition. PMID: 21723849 [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=5041204 Thu, 23 Jun 2011 23:00:00 +0100 5041204 http://www.medworm.com/index.php?rid=5041205&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%3D21723247%26dopt%3DAbstract Authors: Fujita H, Kato T, Watanabe N, Takahashi T, Kitagawa S Calpain inhibitors induce pertussis toxin (PTx)-sensitive chemotaxis in human neutrophils and monocytes. Here, we show that various calpain inhibitors (PD150606, PD151746, N-acetyl-Leu-Leu-Nle-CHO [ALLN], N-acetyl-Leu-Leu-Met-CHO [ALLM], and calpeptin) and γ-secretase inhibitor I induced PTx-sensitive increase in cytoplasmic free Ca(2+) ([Ca(2+)](i)) in human neutrophils and neutrophil migration. HEK-293 cells stably expressing human formyl peptide receptor (hFPR) or hFPR-like 1 (hFPRL1) displayed stimulus-specific increase in [Ca(2+)](i) in response to calpain inhibitors (PD150606, PD151746, ALLN, ALLM, MG-132, and calpeptin), γ-secretase inhibitor I, and N-formyl-Met-Leu-Phe. Parent HEK-293 cells also displayed PTx-sens... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5041205 Wed, 22 Jun 2011 23:00:00 +0100 5041205 http://www.medworm.com/index.php?rid=5041206&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%3D21722622%26dopt%3DAbstract Authors: Roy S, Samanta K, Chakraborti T, Chowdhury A, Chakraborti S We investigated the role of TGF-β1 and TNF-α in mediating the effect of IL-1β in activating proMMP-9 and proMMP-2, and the involvement of an aprotinin sensitive protease in this scenario in bovine pulmonary artery smooth muscle cells. IL-1β induces TGF-β1 mediated stimulation of 92kDa proMMP-9 and 72kDa proMMP-2 mRNA and protein expression; whereas, the elevated level of TNF-α promotes activation of proMMP-9 and proMMP-2. Interestingly, TNF-α induced activation of proMMP-9 appeared to be mediated via a 43kDa aprotinin sensitive protease. TNF-α inhibited aprotinin and TIMP-1 mRNA and protein expression, which apparently facilitated the proteolytic conversion of proMMP-9 to MMP-9 with the involvement of the apro... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=5041206 Tue, 21 Jun 2011 23:00:00 +0100 5041206 http://www.medworm.com/index.php?rid=4997892&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%3D21704604%26dopt%3DAbstract Authors: Meitzler JL, Ortiz de Montellano PR The essential role of human dual oxidase 2 (hDUOX2) in thyroid hormone biosynthesis defines this member of the NOX/DUOX family, whose absence due to mutation has been directly related to disease, specifically hypothyroidism. Both human DUOX isoforms, hDUOX1 and hDUOX2, are expressed in thyroid tissue; however, hDUOX1 cannot compensate for inactivation of hDUOX2, suggesting that each enzyme is differentially regulated and/or functions in a unique manner. In efforts to uncover relevant structural and functional differences we have expressed and purified the peroxidase domain of hDUOX2(1-599) for direct comparison with the previously studied hDUOX1(1-593). As was shown for hDUOX1, the truncated hDUOX2 domain purifies without a bound heme co-fac... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=4997892 Thu, 16 Jun 2011 23:00:00 +0100 4997892 http://www.medworm.com/index.php?rid=4997893&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%3D21704017%26dopt%3DAbstract Authors: Dommaraju SR, Dogovski C, Czabotar PE, Hor L, Smith BJ, Perugini MA Given the rapid rise in antibiotic resistance, including methicillin resistance in Staphylococcus aureus (MRSA), there is an urgent need to characterize novel drug targets. Enzymes of the lysine biosynthesis pathway in bacteria are examples of such targets, including dihydrodipicolinate reductase (DHDPR, E.C. 1.3.1.26), which is the product of an essential bacterial gene. DHDPR catalyzes the NAD(P)H-dependent reduction of dihydrodipicolinate (DHDP) to tetrahydrodipicolinate (THDP) in the lysine biosynthesis pathway. We show that MRSA-DHDPR exhibits a unique nucleotide specificity utilizing NADPH (K(m)=12μM) as a cofactor more effectively than NADH (K(m)=26μM). However, the enzyme is inhibited by high concent... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=4997893 Wed, 15 Jun 2011 23:00:00 +0100 4997893 http://www.medworm.com/index.php?rid=4997894&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%3D21703223%26dopt%3DAbstract Authors: Signorelli S, Möller MN, Coitiño EL, Denicola A Nitrogen dioxide (()NO(2)) is an important oxidant molecule in biology that is produced by several biological processes, and it is also an important air pollutant. It can oxidize proteins and lipids with important consequences on their biological functions. Despite its relevance, the interaction of ()NO(2) with the cell barrier, the lipid membrane, is poorly understood. For instance, can lipid membranes limit ()NO(2) diffusion? To estimate the permeability of lipid membranes to ()NO(2) it is necessary to learn more about its solubility in the lipid phase. However, experimental data on ()NO(2) solubility is very limited. To improve our knowledge on this matter, we used a mixed approach consisting in calculating the solubility of... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=4997894 Tue, 14 Jun 2011 23:00:00 +0100 4997894 http://www.medworm.com/index.php?rid=4948208&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%3D21664504%26dopt%3DAbstract Authors: Walsh MP, Macdonald JA PMID: 21664504 [PubMed - in process] (Source: Archives of Biochemistry and Biophysics) Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=4948208 Tue, 14 Jun 2011 23:00:00 +0100 4948208 http://www.medworm.com/index.php?rid=4948207&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%3D21672512%26dopt%3DAbstract In this study, rational design afforded a variant of Mycobacterium tuberculosis, Mtb-DHDPS-A204R, with disrupted quaternary structure. X-ray crystallography (at a resolution of 2.1Å) revealed a dimeric protein with an identical fold and active-site structure to the tetrameric wild-type enzyme. Analytical ultracentrifugation confirmed the dimeric structure in solution, yet the dimeric mutant has similar activity to the wild-type enzyme. Although the affinity for both substrates was somewhat decreased, the high catalytic competency of the enzyme was surprising in the light of previous results showing that dimeric variants of the Escherichia coli and Bacillus anthracis DHDPS enzymes have dramatically reduced activity compared to their wild-type tetrameric counterparts. These results suggest ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=4948207 Mon, 06 Jun 2011 23:00:00 +0100 4948207 http://www.medworm.com/index.php?rid=4948206&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%3D21672513%26dopt%3DAbstract Authors: Nunes JE, Ducati RG, Breda A, Rosado LA, de Souza BM, Palma MS, Santos DS, Basso LA The emergence of drug-resistant strains of Mycobacterium tuberculosis, the major causative agent of tuberculosis (TB), and the deadly HIV-TB co-infection have led to an urgent need for the development of new anti-TB drugs. The histidine biosynthetic pathway is present in bacteria, archaebacteria, lower eukaryotes and plants, but is absent in mammals. Disruption of the hisD gene has been shown to be essential for M. tuberculosis survival. Here we present cloning, expression and purification of recombinant hisD-encoded histidinol dehydrogenase (MtHisD). N-terminal amino acid sequencing and electrospray ionization mass spectrometry analyses confirmed the identity of homogeneous MtHisD. Analytical ... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=4948206 Sun, 05 Jun 2011 23:00:00 +0100 4948206 http://www.medworm.com/index.php?rid=4948209&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%3D21664341%26dopt%3DAbstract Authors: Misevičienė L, Anusevičius Z, Sarlauskas J, Sevrioukova IF, Cėnas N Mitochondrial apoptosis-inducing factor (AIF) is a FAD-containing protein that under certain conditions translocates to the nucleus and causes a programmed cell death, apoptosis. The apoptogenic action of AIF is redox controlled as the NADH-reduced AIF dimer has lower affinity for DNA than the oxidized monomer. To gain further insights into the mechanism of AIF, we investigated its interaction with a series of quinone oxidants, including a number of anticancer quinones. Our data indicate that the NADH:quinone oxidoreduction catalyzed by AIF follows a "ping-pong" scheme, with the reductive half-reaction being rate-limiting and the FADH(-)-NAD(+) charge-transfer complex serving as an electron donor. AIF is e... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=4948209 Wed, 01 Jun 2011 23:00:00 +0100 4948209 http://www.medworm.com/index.php?rid=4948211&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%3D21658363%26dopt%3DAbstract Authors: Yang H, Chen S, Tang Y, Dai Y Here, we investigated the therapeutic potential of IL-10 by testing its effects on oxLDL-induced lipoprotein uptake and apoptosis by flow cytometry in THP-1-derived macrophages. The mRNA and protein expressions of lipid scavenger receptors (SR-A, CD36) and apoptosis-related proteins (Bcl-2, Bak-1) were also detected. Co-incubation of oxLDL with IL-10 reduced DiI-oxLDL uptake by 16.1±3.8%, 35.2±3.8% and 28.9±1.8% at 6, 12 and 24h of treatment, respectively. Furthermore, treatment with oxLDL for 24h enhanced the SR-A mRNA and protein expressions by 89.3±17.1% and 70.1±17.6%, respectively. IL-10 abrogated the oxLDL-induced SR-A mRNA expression by 50.2±3.9% and its protein by 45.6±1.9%. Meanwhile IL-10 had no effect on the oxLDL-induced increas... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=4948211 Sun, 29 May 2011 23:00:00 +0100 4948211 http://www.medworm.com/index.php?rid=4948210&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%3D21658364%26dopt%3DAbstract This study aimed to elucidate the anti-inflammatory mechanism of genipin, focusing particularly on the role of heme oxygenase-1 (HO-1), a potent anti-inflammatory enzyme. In RAW264.7 cells, genipin increased HO-1 expression and its enzyme activity via a NF-E2-related factor 2 (Nrf2)-antioxidant response element (ARE) pathway. These effects were significantly inhibited by exposure to the phosphatidylinositol 3-kinase (PI 3-kinase) inhibitor, LY294002, or by expression of a dominant negative mutant of PI 3-kinase. Additional experiments showed that the activation of c-Jun NH(2)-terminal kinase 1/2 (JNK1/2) is required for genipin-induced phosphorylation and nuclear translocation of Nrf2 and antioxidant response element (ARE)-driven induction of HO-1, and acts as a downstream effector of PI 3... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=4948210 Sun, 29 May 2011 23:00:00 +0100 4948210 http://www.medworm.com/index.php?rid=4948216&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%3D21640700%26dopt%3DAbstract Authors: Romani AM Magnesium, the second most abundant cellular cation after potassium, is essential to regulate numerous cellular functions and enzymes, including ion channels, metabolic cycles, and signaling pathways, as attested by more than 1000 entries in the literature. Despite significant recent progress, however, our understanding of how cells regulate Mg(2+) homeostasis and transport still remains incomplete. For example, the occurrence of major fluxes of Mg(2+) in either direction across the plasma membrane of mammalian cells following metabolic or hormonal stimuli has been extensively documented. Yet, the mechanisms ultimately responsible for magnesium extrusion across the cell membrane have not been cloned. Even less is known about the regulation in cellular organelles. The... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=4948216 Thu, 26 May 2011 23:00:00 +0100 4948216 http://www.medworm.com/index.php?rid=4948212&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%3D21645492%26dopt%3DAbstract Authors: Sakuraba H, Kawai T, Yoneda K, Ohshima T The crystal structure of a highly thermostable UDP-galactose 4-epimerase (GalE) from the hyperthermophilic archaeon Pyrobaculum calidifontis was determined at a resolution of 1.8Å. The asymmetric unit contained one subunit, and the functional dimer was generated by a crystallographic two-fold axis. Each monomer consisted of a Rossmann-fold domain with NAD bound and a carboxyl terminal domain. The overall structure of P. calidifontis GalE showed significant similarity to the structures of the GalEs from Escherichia coli, human and Trypanosoma brucei. However, the sizes of several surface loops were markedly smaller in P. calidifontis GalE than the corresponding loops in the other enzymes. Structural comparison revealed that the presence... Archives of Biochemistry and Biophysics journals http://www.medworm.com/rss/comments.php?id=4948212 Thu, 26 May 2011 23:00:00 +0100 4948212