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426 records returned

Recognition intensities of submolecular structures, mammalian glyco-structural units, ligand cluster and polyvalency in abrin-a-carbohydrate interactions.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, roles of mammalian glyco-structural units, ligand clusters and polyvalency in abrin-a recognition were comprehensively analyzed by enzyme-linked lectinosorbent binding and inhibition assays. The results indicate that: (i) this toxin prefers oligosaccharides having alpha-anomer of galactose (Gal) at the non-reducing terminal than the corresponding beta-anomer; (ii) Galalpha1-3Galalpha1- (B(alpha)), Galalpha1-4Gal (E), Galbeta1-3GalNAc (T) and Galbeta1-3/4GlcNAc (I/II) related oligosaccharides were the active glyco-structural units; (iii) tri-antennary II(beta), prepared from N-glycan of asialo fetuin, played ...
Source: Biochimie - November 11, 2009 Category: Biochemistry Authors: Wu JH, Wu AM, Yang Z, Chen YY, Singha B, Chow LP, Lin JY Tags: Biochimie Source Type: journals

Characterization of the Structure of the Phosphoprotein of Chandipura Virus, a Negative Stranded RNA Virus Probing Intratryptophan Energy Transfer Using Single and Double Tryptophan Mutants.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The phosphoprotein (P protein) of Chandipura virus (CHPV), a negative stranded RNA virus, is involved in both transcription and replication phases of the viral life cycle. The two Tryptophan (Trp) residues of CHPV, located at 105 and 135 respectively and two single Trp mutants W135F and W105F and a double Trp mutant W135F/W105F have been characterized by steady state and time resolved fluorescence and phosphorescence at 298K and 77K. Results indicate that Trp135 is more buried with less polar and more hydrophobic environment whereas the Trp105 is solvent exposed. Quantum yields (capital EF, Cyrillic) suggest that the s...
Source: Biochimie - November 3, 2009 Category: Biochemistry Authors: Mukhopadhyay S, Maity SS, Roy A, Chattopadhyay D, Ghosh KS, Dasgupta S, Ghosh S Tags: Biochimie Source Type: journals

Molecular size hyaluronan differently modulates toll-like receptor-4 in LPS-induced inflammation in mouse chondrocytes.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Hyaluronan (HA) action depends upon its molecular size. Low molecular weight HA elicits pro-inflammatory responses by modulating the toll-like receptor-4 (TLR-4) or by activating the nuclear factor kappa B (NF-kB). In contrast, high molecular weight HA manifests an anti-inflammatory effect via CD receptors and by inhibiting NF-kB activation. Lipopolysaccharide (LPS) -mediated activation of TLR-4 complex induces the myeloid differentiation primary-response protein (MyD88) and the tumor necrosis factor receptor-associated factor-6 (TRAF-6), and ends with the liberation of NF-kB/Rel family members. The aim of this study w...
Source: Biochimie - October 30, 2009 Category: Biochemistry Authors: Campo GM, Avenoso A, Campo S, D'Ascola A, Nastasi G, Calatroni A Tags: Biochimie Source Type: journals

Phosphorylated intermediate of the ouabain-insensitive, Na(+)-stimulated ATPase in rat kidney cortex and rainbow trout gills.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Several tissues from different animals, including the rat kidney and the fresh water rainbow trout gills, show an ouabain-insensitive, furosemide-sensitive, Na(+)-stimulated ATPase activity, which has been associated with the active control of the cell volume. This Na-ATPase is Mg(2+) dependent and it is inhibited by vanadate, which can be taken as an indication that this enzyme is a P-type ATPase. The P-type ATPases are known to form a phosphorylated intermediate during their catalytic cycle, where the phosphate binds an aspartyl residue at the enzyme's substrate site. In the current study, we partially characterized ...
Source: Biochimie - October 30, 2009 Category: Biochemistry Authors: Ventrella V, Elvir JR, Borgatti AR, Trigari G, Proverbio T, Pagliarani A, Trombetti F, Pirini M, Marín R, Proverbio F Tags: Biochimie Source Type: journals

Astacin-like metalloproteases are a gene family of toxins present in the venom of different species of the brown spider (genus Loxosceles).Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study identified the existence of gene family of astacin-like toxins in the venoms of brown spiders and raises the possibility that these molecules are involved in the deleterious effects triggered by the venom. PMID: 19879318 [PubMed - as supplied by publisher] (Source: Biochimie)
Source: Biochimie - October 29, 2009 Category: Biochemistry Authors: Trevisan-Silva D, Gremski LH, Chaim OM, da Silveira RB, Meissner GO, Mangili OC, Barbaro KC, Gremski W, Veiga SS, Senff-Ribeiro A Tags: Biochimie Source Type: journals

Kinetic properties and specificity of trimeric plasmodium falciparum and human dutpases.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Deoxyuridine 5'-triphosphate nucleotidohydrolase (dUTPase, EC 3.6.1.23) catalyzes the hydrolysis of dUTP to dUMP and pyrophosphate, and plays important roles in nucleotide metabolism and DNA replication. Hydrolysis of other nucleotides similar in structure to dUTP would be physiologically negative and therefore high substrate specificity is essential. Binding and hydrolysis of nucleotides different to dUTP by the dUTPases from Plasmodium falciparum (PfdUTPase) and human (hdUTPase) was evaluated by applying isothermal titration calorimetry (ITC). The ribo and deoxyribonucleoside triphosphates dGTP, dATP, dCTP, dTTP, UTP...
Source: Biochimie - October 28, 2009 Category: Biochemistry Authors: Quesada-Soriano I, Casas-Solvas JM, Recio E, Ruiz-Pérez LM, Vargas-Berenguel A, González-Pacanowska D, García-Fuentes L Tags: Biochimie Source Type: journals

Design of Proton-fueled Tweezers for Controlled, Multi-function DNA-based Molecular Device.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A novel multifunctional, proton fueled DNA tweezers has been constructed. Starting from simple conformation change of i-motif DNA, the nanodevice can accomplish movements such as repeatedly capture or release target DNA and protein. The DNA tweezers, driven by the solution pH without the need of injecting external energy, are robust and highly reversible with the responses of 1-2 orders of magnitude faster than the DNA fuelled machine, and does not accumulate duplex waste products to poison the system. Our work has demonstrated the successful combination of the operating principles of DNA-based nanomechnical device wit...
Source: Biochimie - October 28, 2009 Category: Biochemistry Authors: Song G, Chen M, Chen C, Wang C, Hu D, Ren J, Qu X Tags: Biochimie Source Type: journals

The C-terminal amphipathic alpha-helix of Pseudomonas aeruginosa PelC outer membrane protein is required for its function.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Pseudomonas aeruginosa is an opportunistic pathogen, which causes numerous infections and can adopt a versatile lifestyle. During chronic infection, P. aeruginosa becomes established as a bacterial community known as a biofilm. Biofilm formation results from the production of a matrix mainly comprised of exopolysaccharides. P. aeruginosa possesses several gene clusters which contribute to the formation of the matrix, including the pel genes. Among the pel genes, pelC encodes an outer membrane protein, which may serve as a transporter of polysaccharide to the bacterial cell surface. Whereas outer membrane proteins usual...
Source: Biochimie - October 22, 2009 Category: Biochemistry Authors: Kowalska K, Soscia C, Combe H, Vasseur P, Voulhoux R, Filloux A Tags: Biochimie Source Type: journals

Alterations of matrix metalloproteinases, gastric mucin and prostaglandin E(2) levels by pectic polysaccharide of swallow root (Decalepis hamiltonii) during ulcer healing.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Gastric ulcer is a multi-step disease caused due to imbalance between mucosal defense and aggressive factors. Available anti-ulcer drugs although effective at various steps of ulcer pathogenesity, pose adverse effects. Pectic polysaccharide (SRPP) from swallow root (Decalepis hamiltonii) - previously shown to possess ulcer preventive effect against swim stress and ethanol induced gastric ulcers. In the current study, alteration of matrix metalloproteinases, gastric mucin and prostaglandin E(2) levels during polysaccharide mediated ulcer healing was determined in acetic acid induced gastric ulcer model in Wistar albino ...
Source: Biochimie - October 22, 2009 Category: Biochemistry Authors: Srikanta BM, Sathisha UV, Dharmesh SM Tags: Biochimie Source Type: journals

Maximum rrn promoter activity in Escherichia coli at saturating concentrations of free RNA polymerase.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
During fast growth, the rrn P1 promoters of Escherichia coli operate at their maximum strength, but below their maximum activity (V(max)), since they are not saturated with RNA polymerase. Since higher concentrations of free RNA polymerase are expected to be found in strains carrying rrn deletions, we have analyzed reported electron micrographs of rrn operons from rrn deletion strains growing at maximal rates (at 37 degrees C) in LB medium [1]. We conclude that, in a strain with four of the seven rrn operons inactivated by partial deletions, transcripts are initiated at rrn P1 promoters 1.6-fold more rapidly than in th...
Source: Biochimie - October 14, 2009 Category: Biochemistry Authors: Ehrenberg M, Dennis PP, Bremer H Tags: Biochimie Source Type: journals

Rottlerin induces Heme Oxygenase-1(HO-1) up-regulation through reactive oxygen species (ROS) dependent and PKC delta-independent pathway in human colon cancer HT29 cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, the effect of rottlerin, a putative PKC delta inhibitor, on HO-1 expression in HT29 human colon cancer cells was investigated. Treatment with rottlerin induced HO-1 at both protein and mRNA levels in a dose- and time-dependent manner. Rottlerin-mediated HO-1 induction was abrogated in the presence of N-acetylcysteine (NAC) and glutathione (GSH). Rottlerin induced nuclear translocation of NF-E2-related factor 2 (Nrf2) and increased antioxidant response element (ARE)-driven transcriptional activity. Additionally, rottlerin activated p38 mitogen-activated protein kinase (MAPK) and ERK. The pharmacological inhib...
Source: Biochimie - October 11, 2009 Category: Biochemistry Authors: Park EJ, Lim JH, Nam SI, Park JW, Kwon TK Tags: Biochimie Source Type: journals

Identification of the reactive cysteine residues in yeast dipeptidyl peptidase III.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Dipeptidyl peptidases III (DPPs III) form a distinct metallopeptidase family characterized by the unique HEXXGH motif. High susceptibility to inactivation by organomercurials suggests the presence of a reactive cysteine residue(s) in, or close to, their active site. Yeast DPP III contains five Cys, none of which is absolutely conserved within the family. In order to identify reactive residue(s), site-directed mutagenesis on yeast His(6)-tagged DPP III was employed to substitute specifically all five cysteine residues to serine. The variant enzymes thus obtained were enzymatically active and showed an overall structure ...
Source: Biochimie - October 9, 2009 Category: Biochemistry Authors: Jajčanin-Jozić N, Deller S, Pavkov T, Macheroux P, Abramić M Tags: Biochimie Source Type: journals

Structural and functional evaluation of three well-conserved serine residues in tobacco acetohydroxyacid synthase.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The first step in the common pathway for the biosynthesis of branched-chain amino acids (BCAA) is catalyzed by acetohydroxyacid synthase (AHAS). The roles of three well-conserved serine residues (S167, S506, and S539) in tobacco AHAS were determined using site-directed mutagenesis. The mutations S167F and S506F were found to be inactive and abolished the binding affinity for cofactor FAD. The Far-UV CD spectrum of the inactive mutants was similar to that of wild-type enzyme, indicating no major conformational changes in the secondary structure. However, the active mutants, S167R, S506A, S506R, S539A, S539F and S539R, s...
Source: Biochimie - October 9, 2009 Category: Biochemistry Authors: Yoon MY, Gedi V, Kim J, Park Y, Kim DE, Park EH, Choi JD Tags: Biochimie Source Type: journals

Interaction between lanthanum ion and horseradish peroxidase in vitro.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The interaction between lanthanum ion (La(3+)) and horseradish peroxidase (HRP) in vitro was investigated using a combination of biophysical and biochemical methods. When the molar ratio of La(3+) and HRP is low, it was found that the interaction between La(3+) and HRP mainly depends on the electrostatic attraction, van der waals force and hydrogen bond etc. Thus, the interaction is weak and the La-HRP complex can not be formed in vitro. As expected, the interaction can change the conformation of HRP molecule, leading to the increase in the non-planarity of the porphyrin ring in the heme group of HRP molecule, and then...
Source: Biochimie - October 8, 2009 Category: Biochemistry Authors: Wang L, Lu A, Lu T, Ding X, Huang X Tags: Biochimie Source Type: journals

The membrane-bound mucins: From cell signalling to transcriptional regulation and expression in epithelial cancers.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The membrane-bound mucins belong to an ever-increasing family of O-glycoproteins. Based on their structure and localization at the cell surface they are thought to play important biological roles in cell-cell and cell-matrix interactions, in cell signalling and in modulating biological properties of cancer cells. Among them, MUC1 and MUC4 mucins are best characterized. Their altered expression in cancer (overexpression in the respiratory, gastro-intestinal, urogenital and hepato-biliary tracts) indicates an important role for these membrane-bound mucins in tumour progression, metastasis, cancer cell resistance to chemo...
Source: Biochimie - October 7, 2009 Category: Biochemistry Authors: Jonckheere N, Van Seuningen I Tags: Biochimie Source Type: journals

Increasing the synthesis/hydrolysis ratio of aminoacylase 1 by site-directed mutagenesis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Aminoacylase-1 from pig kidney (pAcy1) catalyzes the highly stereoselective acylation of amino acids, a useful conversion for the preparation of optically pure N-acyl-l-amino acids. The kinetic of this thermodynamically controlled conversion is determined by maximal velocities for synthesis (V(mS)) and hydrolysis (V(mH)) of the N-acyl-l-amino acid. To investigate which parameter affects maximal velocities, we focused on the proton acceptor potential of the catalytic base, E146, and studied the influence of the active site architecture on its contribution to the pKa of residue E146. The modeled structure of pAcy1 identi...
Source: Biochimie - October 7, 2009 Category: Biochemistry Authors: Wardenga R, Lindner HA, Hollmann F, Thum O, Bornscheuer U Tags: Biochimie Source Type: journals

Docosahexaenoic acid modulates the expression of T-bet and GATA-3 transcription factors, independently of PPARalpha, through suppression of MAP kinase activation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The present study was conducted on CD4(+) T cells, isolated from wild type (WT) and PPARalpha(null) mice, in order to assess the mechanism of action of docosahexaenoic acid (DHA), an n-3 fatty acid, in the modulation of two transcription factors, i.e., T-bet and GATA-3, implicated in T-cell differentiation towards, respectively, T(H)1 and T(H)2 phenotype. The T-cells from PPARalpha(null) mice secreted higher IFN-gamma and lower IL-4 concentrations than WT T-cells. Furthermore, the deletion of PPARalpha gene in T-cells resulted in the upregulation of T-bet and downregulation of GATA-3 both at mRNA and protein levels. DH...
Source: Biochimie - September 30, 2009 Category: Biochemistry Authors: Attakpa E, Hichami A, Simonin AM, Sansón EG, Dramane KL, Khan NA Tags: Biochimie Source Type: journals

Sialic acid-binding dwarf elder four-chain lectin displays nucleic acid N-glycosidase activity.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Sialic acid-binding dwarf elder agglutinin (SEA) present only in rhizomes of the medicinal plant Sambucus ebulus L., was found to be a tetrameric glycoprotein consisting of two covalently-associated dimers of an enzymic A chain with rRNA N-glycosidase activity (EC 3.2.2.22) linked to a B chain with agglutinin properties. The lectin inhibited protein synthesis by a cell-free system and depurinated ribosomes. Cloning of the corresponding gene and molecular modeling of the deduced amino acid sequence demonstrated that SEA has a three-dimensional structure which resembles that reported for other two tetrameric type 2 RIPs ...
Source: Biochimie - September 30, 2009 Category: Biochemistry Authors: Iglesias R, Citores L, Ferreras JM, Pérez Y, Jiménez P, Gayoso MJ, Olsnes S, Tamburino R, Di Maro A, Parente A, Girbés T Tags: Biochimie Source Type: journals

The quaternary structure of pyruvate kinase type 1 from E. coli at low nanomolar concentrations.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Pyruvate kinase (PK) is the key control point of glycolysis-the biochemical pathway central to energy metabolism and the production of precursors used in biosynthesis. PK type 1 from Escherichia coli (Ec-PK1) is activated by both fructose-1,6-bisphosphate (FBP) and its substrate, phosphoenol pyruvate (PEP). To date, it has not been possible to determine whether the enzyme is tetrameric at the low concentrations (i.e. low nM range) used to study the steady state kinetics, or assess whether its allosteric effectors alter the oligomeric state of the enzyme at these concentrations. Employing the new technique of analytical...
Source: Biochimie - September 30, 2009 Category: Biochemistry Authors: Zhu T, Bailey MF, Angley LM, Cooper TF, Dobson RC Tags: Biochimie Source Type: journals

Characterisation of n-glycans bound to IGFBP-3 in sera from healthy adults.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study represents a ground for the future research of glycosylation pattern of IGFBP-3 from the circulation of men and women diagnosed with different illnesses. PMID: 19800385 [PubMed - as supplied by publisher] (Source: Biochimie)
Source: Biochimie - September 29, 2009 Category: Biochemistry Authors: Masnikosa R, Baričević I, Lagundžin D, Nedić O Tags: Biochimie Source Type: journals

Aldose-6-phosphate reductase from apple leaves:Importance of the quaternary structure for enzyme activity.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Aldose-6-phosphate reductase (A6PRase) is a key enzyme for glucitol biosynthesis in plants from the Rosaceae family. To gain on molecular tools for enzymological studies, we developed an accurate system for the heterologous expression of A6PRase from apple leaves. The recombinant enzyme was expressed with a His-tag alternatively placed in the N-or C-terminus, thus allowing the one-step protein purification by immobilized metal affinity chromatography. Both, the N-and theC-term tagged enzymes exhibited similar affinity toward substrates, although thek(cat) of the latter enzyme was 80-fold lower than that having the His-...
Source: Biochimie - September 28, 2009 Category: Biochemistry Authors: Figueroa CM, Iglesias AA Tags: Biochimie Source Type: journals

Molecular dynamics analysis of the wild type and dF508 mutant structures of the human CFTR-nucleotide binding domain 1.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mutations of CFTR (Cystic Fibrosis transmembrane Conductance Regulator), a membrane protein expressed in the epithelium, a chloride channel cause a chronic, developmental and hereditary disease, known as Cystic Fibrosis. The most common mutation is the deletion of F508, the residue present in the first nucleotide binding domain (NBD1). We studied the thermodynamic properties of NBD1 wild type (WT) and mutant (dF508), starting from the crystallographic structures in the Protein Data Bank using the techniques of Molecular Dynamics. The two structures were similarly stable at room temperature, showed no change enthalpy or...
Source: Biochimie - September 23, 2009 Category: Biochemistry Authors: Bisignano P, Moran O Tags: Biochimie Source Type: journals

Contraceptive steroids from pharmaceutical waste perturbate junctional communication in sertoli cells.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The potential health impact of pharmaceutical waste is now a growing concern. Contraceptive steroids are prominent environmental contaminants and thus may act as endocrine disruptors. Numerous xenobiotics hamper Sertoli cells junctional communication which is known to participate in spermatogenesis control. This has been associated with male subfertility and testicular cancer. We investigated three contraceptive molecules found in the environment for their potential impact on Sertoli cells gap junction functionality: 17a-ethynylestradiol, medroxyprogesterone acetate and levonorgestrel. Four other non-steroid drugs also...
Source: Biochimie - September 20, 2009 Category: Biochemistry Authors: Tramoni M, Gilleron J, Tahiri K, Carette D, Corvol MT, Segretain D, Pointis G, Savouret JF Tags: Biochimie Source Type: journals

Differential scanning calorimetric and spectroscopic studies on the unfolding of Momordica charantia lectin. Similar modes of thermal and chemical denaturation.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Thermal stability of Momordica charantia seed lectin (MCL) was investigated as a function of protein concentration, pH, scan rate, and at different ligand concentrations by using high-sensitivity differential scanning calorimetry (DSC). The DSC endotherm obtained at pH 7.4 consists of two entities with transition temperatures at ca. 333.7 K, and 338 K. The unfolding process is irreversible and could be described by a three-state model. For MCL tetramer DeltaH(c)/DeltaH(v) ratio is close to 4 for the first transition and approximately 2 for the second transition, suggesting that four and two cooperative units are involv...
Source: Biochimie - September 20, 2009 Category: Biochemistry Authors: Kavitha M, Bobbili KB, Swamy MJ Tags: Biochimie Source Type: journals

Modulation of the hepatic fatty acid pool in peroxisomal 3-ketoacyl-CoA thiolase B-null mice exposed to the selective PPARalpha agonist Wy14,643.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The peroxisomal 3-ketoacyl-CoA thiolase B (Thb) gene was previously identified as a direct target gene of PPARalpha, a nuclear hormone receptor activated by hypolipidemic fibrate drugs. To better understand the role of ThB in hepatic lipid metabolism in mice, Sv129 wild-type and Thb null mice were fed or not the selective PPARalpha agonist Wy14,643 (Wy). Here, it is shown that in contrast to some other mouse models deficient for peroxisomal enzymes, the hepatic PPARalpha signalling cascade in Thb null mice was normal under regular conditions. It is of interest that the hypotriglyceridemic action of Wy was reduced in Th...
Source: Biochimie - September 18, 2009 Category: Biochemistry Authors: Arnauld S, Fidaleo M, Clémencet MC, Chevillard G, Athias A, Gresti J, Wanders RJ, Latruffe N, Nicolas-Francès V, Mandard S Tags: Biochimie Source Type: journals

Structure and function of Plasmodium falciparum malate dehydrogenase: Role of critical amino acids in co-substrate binding pocket.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The malaria parasite thrives on anaerobic fermentation of glucose for energy. Earlier studies from our laboratory have demonstrated that a cytosolic malate dehydrogenase (PfMDH) with striking similarity to lactate dehydrogenase (PfLDH) might complement PfLDH function in Plasmodium falciparum. The N-terminal glycine motif, which forms a characteristic Rossman dinucleotide-binding fold in the co-substrate binding pocket, differentiates PfMDH (GlyXGlyXXGly) from other eukaryotic and prokaryotic malate dehydrogenases (GlyXXGlyXXGly). The amino acids lining the co-substrate binding pocket are completely conserved in MDHs fr...
Source: Biochimie - September 18, 2009 Category: Biochemistry Authors: Pradhan A, Tripathi AK, Desai PV, Mukherjee PK, Avery MA, Walker LA, Tekwani BL Tags: Biochimie Source Type: journals

FAD binding in glycine oxidase from Bacillus subtilis.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The apoprotein of the FAD-containing flavoenzyme glycine oxidase from Bacillus subtilis was obtained at pH 8.5 by dialyzing the holoenzyme against 2 M KBr in 0.25 M Tris-HCl and 20% glycerol. The apoprotein of glycine oxidase shows high protein fluorescence, high exposure of hydrophobic surfaces, and low temperature stability as compared to the holoenzyme. The isolated apoprotein species is present in solution as a monomer which rapidly recovers its tertiary structure and converts into the tetrameric holoenzyme following incubation with free FAD. The reconstitution process follows a particular two-stage process; the sp...
Source: Biochimie - September 10, 2009 Category: Biochemistry Authors: Caldinelli L, Pedotti M, Motteran L, Molla G, Pollegioni L Tags: Biochimie Source Type: journals

Nitrochalcones: Potential in vivo insulin secretagogues.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, the in vivo and in vitro anti-hyperglycemic activity of chalcone derivatives of 3,4-methylenedioxy, with a substituent electron-acceptor nitro group in the A or B ring, was investigated. As expected, the second generation sulfonylurea glipizide stimulated insulin secretion and reduced glycemia over the study period. Also, it was demonstrated for the first time that chalcones are able to increase insulin secretion and this event was coincident with serum glucose-lowering in the oral glucose tolerance test. Additionally, the chalcones studied had a similar effect on insulin secretion and serum glucose-lowering...
Source: Biochimie - September 8, 2009 Category: Biochemistry Authors: Damazio RG, Zanatta AP, Cazarolli LH, Mascarello A, Chiaradia LD, Nunes RJ, Yunes RA, Silva FR Tags: Biochimie Source Type: journals

Phosphate facilitates Fe(II) oxidative deposition in pea seed (Pisum sativum) ferritin.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The iron core within phytoferritin interior usually contains the high ratio of iron to phosphate, agreeing with the fact that phosphorus and iron are essential nutrient elements for plant growth. It was established that iron oxidation and incorporation into phytoferritin shell occurs in the plastid(s) where the high concentration of phosphate occurs. However, so far, the role of phosphate in iron oxidative deposition in plant ferritin has not been recognized yet. In the present study, Fe(II) oxidative deposition in pea seed ferritin (PSF) was aerobically investigated in the presence of phosphate. Results indicated that...
Source: Biochimie - September 3, 2009 Category: Biochemistry Authors: Li C, Qi X, Li M, Zhao G, Hu X Tags: Biochimie Source Type: journals

Identification of continuous interaction sites in PLA(2)-based protein complexes by peptide arrays.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Crotoxin (CA.CB) is a beta-neurotoxin from Crotalus durissus terrificus snake venom that is responsible for main envenomation effects upon biting by this snake. It is a heterodimer of an acidic protein (CA) devoid of any biological activity per se and a basic, enzymatically active, PLA(2) counterpart (CB). Both lethal and enzymatic activities of crotoxin have been shown to be inhibited by CNF, a protein from the blood of C. d. terrificus snakes. CNF replaces CA in the CA.CB complex, forming a stable, non-toxic complex CNF.CB. The molecular sites involved in the tight interfacial protein-protein interactions in these PL...
Source: Biochimie - September 2, 2009 Category: Biochemistry Authors: Fortes-Dias CL, Santos RM, Magro AJ, Fontes MR, Chávez-Olórtegui C, Granier C Tags: Biochimie Source Type: journals

Natural compounds and the hypoxia-inducible factor (HIF) signalling pathway.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
A decline in the tissue oxygen level below normal leads to cellular hypoxia. This situation is very frequently encountered in solid tumors as existing blood vessels cannot satisfy the requirements in oxygen of the rapidly growing tumor. Like hyperoxia, hypoxia is a stress factor for cells and tissues. Adapting to this stressful situation leads to activation of the dimeric transcription factor hypoxia-inducible factor-1 (HIF-1) that induces gene expression in promoting tumor cell survival. In addition, hypoxia acts as a selection factor for radio- and chemo-therapy resistant tumor cells with a high potential of malignan...
Source: Biochimie - August 20, 2009 Category: Biochemistry Authors: Manolescu B, Oprea E, Busu C, Cercasov C Tags: Biochimie Source Type: journals

High aryl acylamidase activity associated with cobra venom acetylcholinesterase: Biological significance.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Investigation of the non-classical functions of cholinesterases (ChEs) has been the subject of interest in the past three decades. One of which is aryl acylamidase (AAA) activity associated with ChEs, but characterized in in vitro, as an enzyme, splitting the artificial substrate o-nitroacetanilide with unknown physiological function. In the present study, we have compared levels of AAA activity of AChE from different sources like goat brain, electric eel organ and from venoms of different snakes. Remarkably cobra venom showed the highest AAA activity and also high AAA/AChE ratio. Both serotonergenic and cholinergic in...
Source: Biochimie - August 16, 2009 Category: Biochemistry Authors: Rajesh RV, Layer PG, Boopathy R Tags: Biochimie Source Type: journals

The first alpha-1,3-glucosidase from bacterial origin belonging to glycoside hydrolase family 31.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Genome analysis of Lactobacillus johnsonii NCC533 has been recently completed. One of its annotated genes, lj0569, encodes the protein having the conserved domain of glycoside hydrolase family 31. Its homolog gene (ljag31) in L. johnsonii NBRC13952 was cloned and expressed using an Escherichia coli expression system, resulting in poor production of recombinant LJAG31 protein due to inclusion body formation. Production of soluble recombinant LJAG31 was improved with high concentration of NaCl in medium, possible endogenous chaperone induction by benzyl alcohol, and over-expression of GroES-GroEL chaperones. Recombinant ...
Source: Biochimie - August 12, 2009 Category: Biochemistry Authors: Kang MS, Okuyama M, Mori H, Kimura A Tags: Biochimie Source Type: journals

Revisiting Delta-6 Desaturase regulation by C18 unsaturated fatty acids, depending on the nutritional status.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Dietary polyunsaturated fatty acids (PUFA) play a key role in regulating delta-6 desaturase (D6D), the key enzyme for long chain PUFA biosynthesis. Nevertheless, the extent of their effects on this enzyme remains controversial and difficult to assess. It has been generally admitted that C18 unsaturated fatty acids (UFAs) regulate negatively delta-6 desaturase (D6D). This inhibition has been evidenced in regard to a high glucose/fat free (HG/FF) diet used in reference. However, several nutritional investigations did not evidence any inhibition of desaturases when feeding fatty acids. Because the choice of the basal diet...
Source: Biochimie - August 9, 2009 Category: Biochemistry Authors: Skrzypski J, Bellenger S, Bellenger J, Sinclair A, Poisson JP, Tessier C, Rialland M, Narce M Tags: Biochimie Source Type: journals

Dissimilarity in the channel intrinsic stability among the bacterial KcsA and the inwardly rectifying potassium channel ROMK1.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, we compared the channel intrinsic stability of the bacterial K(+)-channel KcsA and the inwardly rectifying potassium channel (Kir) ROMK1. ROMK1 was successfully cloned, expressed and purified from Saccharomyces cerevisae. By conventional gel electrophoresis, ROMK1 was detected in monomeric form running exclusively at ~45 kDa either in its oxidized or reduced form. By perfluoro-octanoic acid (PFO)-PAGE, the reduced ROMK1 was identified as tetrameric as well as oligomeric complex. However, in its oxidized form ROMK1 was exclusively detected in oligomeric form thus indicating the role of intrinsic cysteine resi...
Source: Biochimie - August 9, 2009 Category: Biochemistry Authors: Raja M, Vales E Tags: Biochimie Source Type: journals

Plasma fatty acid levels may regulate the Zn(2+)-dependent activities of histidine-rich glycoprotein.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Histidine-rich glycoprotein (HRG) is a plasma adaptor protein involved in the formation of protein complexes that regulate a number of biological processes in the blood, most notably coagulation and the immune system. Elevated levels of HRG are clinically linked to thrombotic disorders such as blood vessel occlusion. A large body of evidence suggests that Zn(2+) ions stimulates HRG-complex formation; however, under normal conditions the vast majority of Zn(2+) in the blood is bound to human serum albumin (HSA). We have previously demonstrated that high levels of fatty acid act as an allosteric switch which disrupts the...
Source: Biochimie - August 9, 2009 Category: Biochemistry Authors: Stewart AJ, Blindauer CA, Sadler PJ Tags: Biochimie Source Type: journals

Characterization of papain-like isoenzymes from latex of Asclepias curassavica by molecular biology validated by proteomic approach.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Latices from Asclepias spp are used in wound healing and the treatment of some digestive disorders. These pharmacological actions have been attributed to the presence of cysteine proteases in these milky latices. Asclepias curassavica (Asclepiadaceae),"scarlet milkweed " is a perennial subshrub native to South America. In the current paper we report a new approach directed at the selective biochemical and molecular characterization of asclepain cI (acI) and asclepain cII (acII), the enzymes responsible for the proteolytic activity of the scarlet milkweed latex. SDS-PAGE spots of both purified peptidases were digested w...
Source: Biochimie - August 9, 2009 Category: Biochemistry Authors: Obregón WD, Liggieri CS, Trejo SA, Avilés FX, Vairo-Cavalli SE, Priolo NS Tags: Biochimie Source Type: journals

Prediction of the protein folding core: application to the immunoglobulin fold.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We propose an algorithm that allows predicting residues important for the formation of the structure of globular proteins. It relies on a simulation that detects the amino acids presenting a maximum number of neighbours during the early steps of the folding process. They have been called MIR (Most Interacting Residues). Independently, description of the protein structures in fragments with closed ends shows the correlation between these extremities and the core of the globules. These fragments are of rather constant length, typically between 20 and 25 amino acids, and we have previously shown that their extremities are...
Source: Biochimie - August 4, 2009 Category: Biochemistry Authors: Prudhomme N, Chomilier J Tags: Biochimie Source Type: journals

2'-phosphodiesterase and 2',5'-oligoadenylate synthetase activities in the lowest metazoans, sponge [porifera].Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Sponges [porifera], the most ancient metazoans, contain modules related to the vertebrate immunity system, including the 2',5'-oligoadenylate synthetase (OAS). The components of the antiviral 2',5'-oligoadenylate (2-5A) system (OAS, 2'-Phosphodiesterase (2'-PDE) and RNAse L) of vertebrates have not all been identified in sponges. Here, we demonstrate for the first time that in addition to the OAS activity, sponges possess a 2'-PDE activity, which highlights the probable existence of a premature 2-5A system. Indeed, Suberites domuncula and Crella elegans exhibited this 2-5A degrading activity. Upon this finding, two out...
Source: Biochimie - August 4, 2009 Category: Biochemistry Authors: Saby E, Poulsen JB, Justesen J, Kelve M, Uriz MJ Tags: Biochimie Source Type: journals

The human large subunit ribosomal protein L36A-like contacts the CCA end of P-site bound tRNA.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Periodate-oxidized tRNA (tRNAox), the 2',3'-dialdehyde derivative of tRNA, was used as a zero-length active site-directed affinity labeling reagent, to covalently label proteins at the binding site for the 3'-end of tRNA on human 80S ribosomes. When human 80S ribosomes were reacted with tRNA(Asp)ox positioned at the P-site, in the presence of an appropriate 12 mer mRNA, a set of two tRNAox-labeled ribosomal proteins (rPs) was observed. The majorily labeled protein was identified as the large subunit rP L36a-like (RPL36AL) by means of mass spectrometry. Intact tRNA(Asp) competed with tRNA(Asp)ox for the binding to the P...
Source: Biochimie - July 29, 2009 Category: Biochemistry Authors: Baouz S, Woisard A, Sinapah S, Le Caer JP, Argentini M, Bulygin K, Aguié G, Hountondji C Tags: Biochimie Source Type: journals

N-myristoylation targets dihydroceramide Delta4-desaturase 1 to mitochondria: Partial involvement in the apoptotic effect of myristic acid.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
This study was designed to analyze the effect of myristic acid on ceramide synthesis and its related lipoapoptosis pathway. It was previously observed that myristic acid binds dihydroceramide Delta4-desaturase 1 (DES1) through N-myristoylation and activates this enzyme involved in the final de novo ceramide biosynthesis step. In the present study, we show first by immunofluorescence microscopy and subcellular fractionation that DES1 myristoylation targets part of the recombinant protein to the mitochondria in COS-7 cells. In addition, native dihydroceramide Delta4-desaturase activity was found in both the endoplasmic retic...
Source: Biochimie - July 28, 2009 Category: Biochemistry Authors: Beauchamp E, Tekpli X, Marteil G, Lagadic-Gossmann D, Legrand P, Rioux V Tags: Biochimie Source Type: journals

Wilson Disease: Current Status and the Future.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The focus of this minireview is on the current status and new advances in diagnosis and treatment of Wilson disease, an autosomal recessive disorder of copper metabolism. Molecular diagnostics have improved and complements current biochemical and clinical methods for screening for Wilson disease. Screening for Wilson disease in newborns is feasible and has been tested in limited populations, but is not yet widely performed. Identification of patients with Wilson disease as the cause lof acute liver failure is possible using standard biochemical tests. Treatments for Wilson disease include chelating agents and zinc salt...
Source: Biochimie - July 28, 2009 Category: Biochemistry Authors: Schilsky ML Tags: Biochimie Source Type: journals

Metals in health: From cell to soil, a multiscale approach.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
PMID: 19631250 [PubMed - as supplied by publisher] (Source: Biochimie)
Source: Biochimie - July 21, 2009 Category: Biochemistry Authors: Curis E, Nicolis I, Bénazeth S Tags: Biochimie Source Type: journals

Enzymatic characterization of a monomeric isocitrate dehydrogenase from Streptomyces lividans TK54.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Isocitrate dehydrogenase (IDH) is one of the key enzymes in the citric acid cycle, which involves in providing energy and biosynthetic precursors for metabolism. Here, we report for the first time the enzymatic characterization of a monomeric NADP(+)-dependent IDH from Streptomyces lividans TK54 (SlIDH). The icd gene (GenBank database accession number EU661252) encoding IDH was cloned and overexpressed in Escherichia coli. The molecular mass of SlIDH was about 80 kDa, typical of a monomeric NADP-IDH, and showed high amino acid sequence identity with known monomeric IDHs. The optimal activity of the 6His-tagged SlIDH wa...
Source: Biochimie - July 21, 2009 Category: Biochemistry Authors: Zhang B, Wang B, Wang P, Cao Z, Huang E, Hao J, Dean AM, Zhu G Tags: Biochimie Source Type: journals

Platelet derived growth factor BB is a ligand for dermatan sulfate chain(s) of small matrix proteoglycans from normal and fibrosis affected fascia.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We examined by the solid phase assay the growth factor binding to DS chains of small proteoglycans from various fasciae as well as to standard CSs. Before the assay a structural analysis of DSs and CSs was accomplished involving the evaluation of their epimerization and/or sulfation patterns. In addition, in vivo acceptors for PDGF-BB in fibrosis affected fascia were detected. PDGF-BB binding sites on DSs/CSs are located in long chain sections with the same type of hexuronate isomer however without any apparent preference to glucuronate or iduronate residues. Alternatively, the interaction seems to involve two shorter DS c...
Source: Biochimie - July 21, 2009 Category: Biochemistry Authors: Koźma EM, Wisowski G, Olczyk K Tags: Biochimie Source Type: journals

Are there three polynucleotide strands in the catalytic center of DNA polymerases?Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
Mitochondrial DNA may undergo large-scale rearrangements, thus leading to diseases. The mechanisms of these rearrangements are still the matter of debates. Several lines of evidence indicate that breakpoints are characterized by direct repeats (DR), one of them being eliminated from the normal genome. Analysis of DR showed their skewed nucleotide content compatible with the formation of known triple helices. Here, I propose a novel mechanism involving the formation of triplex structures that result from the dissociation of the [synthesized repeat-DNA polymerase] complex. Upon binding to the homologous sequence, replica...
Source: Biochimie - July 19, 2009 Category: Biochemistry Authors: Lestienne PP Tags: Biochimie Source Type: journals

Metallomics integrated with proteomics in deciphering metal-related environmental issues.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
The present work shows the possibilities of metallomics to characterize metal-linking proteins in Mus Musculus that could be used in environmental assessment. The laboratory mouse M. musculus is used as reference of gene/protein sequence databases to address methodological approaches based on changes in transcripts regulation, proteins expression and metalloproteins profiles in the environmental bioindicator Mus spretus that has been demonstrated to be genetically homologous to M. Musculus. A metallomic approach using size exclusion chromatography with inductively coupled plasma-mass spectrometry detection (SEC-ICP-MS)...
Source: Biochimie - July 17, 2009 Category: Biochemistry Authors: González-Fernández M, García-Barrera T, Jurado J, Pueyo C, López-Barea J, Gómez-Ariza JL Tags: Biochimie Source Type: journals

Peptide Derived from the Lipid Binding Domain of Group IB Human Pancreatic Phospholipase A(2) Possesses Antibacterial Activity.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study we report the antibacterial properties of a peptide (AVWQFRKMIK-CONH(2); N10 peptide), which corresponds to the N-terminal first ten amino acid residues of hp-sPLA(2), against E.coli. Full-length hp-sPLA(2), which contains this peptide sequence as N-terminal alpha-helix, did not showed detectable antibacterial activity. Presence of physiological concentration of salt or preincubation of N10 peptide with soluble anionic polymer inhibits the antibacterial activity indicating the importance of electrostatic interaction in binding of peptide to bacterial membrane. Addition of peptide resulted in destabilization o...
Source: Biochimie - July 16, 2009 Category: Biochemistry Authors: Limbachiya MS, Pande AH Tags: Biochimie Source Type: journals

EXAFS structural study of platinum-based anticancer drugs degradation in presence of sulfur nucleophilic species.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
We present the main structural results we have obtained concerning the reaction of these drugs with diverse sulfur nucleophiles (cysteine, glutathione, methionine, thiosulfate and thiocyanate), monitored in solution or as precipitates by EXAFS spectroscopy. The reactivities of the carboxylate and amine ligands of both carboplatin and oxaliplatin are compared, on the basis of first coordination sphere modeling. Among the new results of this EXAFS study, we present the first observation of oxaliplatin diaminocyclohexane ligand displacement by sulfur nucleophiles. PMID: 19607872 [PubMed - as supplied by publisher] (Source: Biochimie)
Source: Biochimie - July 12, 2009 Category: Biochemistry Authors: Provost K, Bouvet-Muller D, Crauste-Manciet S, Olivi L, Vlaic G, Michalowicz A Tags: Biochimie Source Type: journals

The aryl acylamidase activity is much more sensitive to Alzheimer drugs than the esterase activity of acetylcholinesterase in chicken embryonic brain.Email this article to a colleague. Save this article to My Clippings. Discuss or comment on this article.
In this study, an attempt has been made in profiling esterase and AAA activities of AChE at different developmental stages of the chick embryo, e.g. at embryonic day 6 (E6), E9, E12, E15 and E18. AAA activity showed a correlated expression with esterase activity at all stages, but the relative ratios of AAA to esterase activity were higher at younger stages. The inhibition of AAA activity was shown to be more sensitive towards Huperzine, Donepezil whereas inhibition of esterase activity was sensitive to Tacrine and DFP. Remarkably, the major Alzheimer drugs- Huperzine and Donepezil, much more strongly inhibited AAA activit...
Source: Biochimie - July 10, 2009 Category: Biochemistry Authors: Rajesh RV, Chitra L, Layer PG, Boopathy R Tags: Biochimie Source Type: journals