Search results for "SAC"
showing 10 items of 3337 documents
Signaling pathways of the TREM-1- and TLR4-mediated neutrophil oxidative burst.
2008
The triggering receptor expressed on myeloid cells 1 (TREM-1) is involved in the innate inflammatory response to microbial infections. Activation and expression of TREM-1 by polymorphonuclear neutrophils (PMN) occurs in concert with Toll-like receptors (TLR) such as TLR4 for bacterial lipopolysaccharide. However, it is currently unclear how this is mediated on a molecular level. Using pharmacological inhibitors and Western blot analysis we demonstrate that phosphatidyl inositide 3-kinase, phospholipase C and the mitogen-activated kinase p38MAPK are essential for the TREM-1- and TLR4-induced oxidative burst of human PMN. The activation of protein kinase B and extracellular signal-related kin…
The unique structure of complete lipopolysaccharide isolated from semi-rough Plesiomonas shigelloides O37 (strain CNCTC 39/89) containing (2S)-O-(4-o…
2013
The complete structure of semi-rough lipopolysaccharide (SR-LPS) of Plesiomonas shigelloides CNCTC 39/89 (serotype O37) has been investigated by (1)H and (13)C NMR spectroscopy, matrix-assisted laser-desorption/ionization time-of-flight MS, and chemical methods. The following structure of the single unit of the O-antigen has been established: [formula see text] in which α-D-Lenp is (2S)-O-(4-oxopentanoic acid)-α-D-Glcp residue which has not been found in nature. The absolute configuration of oxopentanoic acid moiety in α-d-Lenose residue was determined by NOESY experiment combined with molecular modeling (MM2 force field). The decasaccharide core is substituted at C-4 of the β-D-Glcp residu…
The Protein Structure Context of PolyQ Regions.
2016
Proteins containing glutamine repeats (polyQ) are known to be structurally unstable. Abnormal expansion of polyQ in some proteins exceeding a certain threshold leads to neurodegenerative disease, a symptom of which are protein aggregates. This has led to extensive research of the structure of polyQ stretches. However, the accumulation of contradictory results suggests that protein context might be of importance. Here we aimed to evaluate the structural context of polyQ regions in proteins by analysing the secondary structure of polyQ proteins and their homologs. The results revealed that the secondary structure in polyQ vicinity is predominantly random coil or helix. Importantly, the region…
Concentration dependent effects of commonly used pesticides on activation versus inhibition of the quince (Cydonia Oblonga) polyphenol oxidase
2009
Polyphenol oxidase (PPO) catalyzes the oxidation of o-diphenols to their respective quinones which undergo autopolymerization and form dark pigments. The interaction of PPO with various substrates and effectors remains the focus of intensive investigations due to the enzyme's key role in pigments biosynthesis including animal melanogenesis and fruit/fungi enzymatic browning. In this study, the effect of a range of commonly used pesticides on the enzyme activity has been evaluated using the purified quince (Cydonia oblonga Miller) PPO. The biochemical analysis showed that, in the presence of high pesticide concentrations, the enzyme was competitively inhibited, particularly with benomyl, car…
Structural Characterization of Set1 RNA Recognition Motifs and their Role in Histone H3 Lysine 4 Methylation
2006
Departament de Bioquimica iBiologia Molecular, Universitatde Valencia, C/Dr Moliner 50,46100, Burjassot, SpainThe yeast Set1 histone H3 lysine 4 (H3K4) methyltransferase contains, inaddition to its catalytic SET domain, a conserved RNA recognition motif(RRM1). We present here the crystal structure and the secondary structureassignment in solution of the Set1 RRM1. Although RRM1 has the expectedβαββαβ RRM-fold, it lacks the typical RNA-binding features of thesemodules. RRM1 is not able to bind RNA by itself in vitro, but a constructcombining RRM1 with a newly identified downstream RRM2 specificallybinds RNA. Invivo,H3K4 methylation isnot affectedbyapoint mutation inRRM2 that preserves Set1 s…
Structures of yeast peroxisomal Δ(3),Δ(2)-enoyl-CoA isomerase complexed with acyl-CoA substrate analogues: the importance of hydrogen-bond networks f…
2015
Δ3,Δ2-Enoyl-CoA isomerases (ECIs) catalyze the shift of a double bond from 3Z- or 3E-enoyl-CoA to 2E-enoyl-CoA. ECIs are members of the crotonase superfamily. The crotonase framework is used by many enzymes to catalyze a wide range of reactions on acyl-CoA thioesters. The thioester O atom is bound in a conserved oxyanion hole. Here, the mode of binding of acyl-CoA substrate analogues to peroxisomalSaccharomyces cerevisiaeECI (ScECI2) is described. The best defined part of the bound acyl-CoA molecules is the 3′,5′-diphosphate-adenosine moiety, which interacts with residues of loop 1 and loop 2, whereas the pantetheine part is the least well defined. The catalytic base, Glu158, is hydrogen-bo…
Homology modeling using simulated annealing of restrained molecular dynamics and conformational search calculations with CONGEN: application in predi…
1997
We have developed an automatic approach for homology modeling using restrained molecular dynamics and simulated annealing procedures, together with conformational search algorithms available in the molecular mechanics program CONGEN (Bruccoleri RE, Karplus M, 1987, Biopolymers 26:137-168). The accuracy of the method is validated by "predicting" structures of two homeodomain proteins with known three-dimensional structures, and then applied to predict the three-dimensional structure of the homeodomain of the murine Msx-1 transcription factor. Regions of the unknown protein structure that are highly homologous to the known template structure are constrained by "homology distance constraints,"…
Crystal structure of vinorine synthase, the first representative of the BAHD superfamily.
2005
Vinorine synthase is an acetyltransferase that occupies a central role in the biosynthesis of the antiarrhythmic monoterpenoid indole alkaloid ajmaline in the plant Rauvolfia. Vinorine synthase belongs to the benzylalcohol acetyl-, anthocyanin-O-hydroxy-cinnamoyl-, anthranilate-N-hydroxy-cinnamoyl/benzoyl-, deacetylvindoline acetyltransferase (BAHD) enzyme superfamily, members of which are involved in the biosynthesis of several important drugs, such as morphine, Taxol, or vindoline, a precursor of the anti-cancer drugs vincaleucoblastine and vincristine. The x-ray structure of vinorine synthase is described at 2.6-angstrom resolution. Despite low sequence identity, the two-domain structure…
Characterization of aCandida albicansgene encoding a putative transcriptional factor required for cell wall integrity
2003
After screening a Candida albicans genome database the product of an open reading frame (ORF) (CA2880) with 49% homology to the product of Saccharomyces cerevisiae YPL133c, a putative transcriptional factor, was identified. The disruption of the C. albicans gene leads to a major sensitivity to calcofluor white and Congo red, a minor sensitivity to sodium dodecyl sulfate, a major resistance to zymolyase, and an alteration of the chemical composition of the cell wall. For these reasons we called it CaCWT1 (for C. albicans cell wall transcription factor). CaCwt1p contains a putative Zn(II) Cys(6) DNA binding domain characteristic of some transcriptional factors and a PAS domain. The CaCWT1 gen…
Effect of tin and lead chlorotriphenyl analogues on selected living cells.
2010
Three kinds of living cells, human embryonic kidney cells, Saccharomyces cerevisiae, and Escherichia coli, were tested for their sensitivity to chlorotriphenyltin and chlorotriphenyllead. The tin compound proved definitely more toxic than the lead derivative, particularly in the case of the human embryonic kidney cells devoid of any protective cell wall. Electron paramagnetic resonance (EPR) comparative studies carried out by using a natural model liposome system (egg yolk lecithin) confirmed considerable changes within the lipid bilayer upon doping by the aforementioned additives, which may be crucial to the mechanism of the observed cell cleavage. The individual dopants revealed diverse i…