1z76
Crystal structure of an acidic phospholipase A2 (BthA-I) from Bothrops jararacussu venom complexed with p-bromophenacyl bromide
Structural highlights
FunctionPA2A_BOTJR Snake venom phospholipase A2 (PLA2) that induces edema (activity that is inhibited by EDTA and dexamethasone), inhibits phospholipid-dependent collagen/ADP-induced platelet aggregation, possess hypotensive as well as anticoagulant activities. In addition, this enzyme shows bactericidal activity against E.coli and S.aureus. PLA2 catalyzes the calcium-dependent hydrolysis of the 2-acyl groups in 3-sn-phosphoglycerides.[1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe crystal structure of an acidic phospholipase A(2) isolated from Bothrops jararacussu venom (BthA-I) chemically modified with p-bromophenacyl bromide (BPB) has been determined at 1.85 Angstroms resolution. The catalytic, platelet-aggregation inhibition, anticoagulant and hypotensive activities of BthA-I are abolished by ligand binding. Electron-density maps permitted unambiguous identification of inhibitor covalently bound to His48 in the substrate-binding cleft. The BthA-I-BPB complex contains three structural regions that are modified after inhibitor binding: the Ca(2+)-binding loop, beta-wing and C-terminal regions. Comparison of BthA-I-BPB with two other BPB-inhibited PLA(2) structures suggests that in the absence of Na(+) ions at the Ca(2+)-binding loop, this loop and other regions of the PLA(2)s undergo structural changes. The BthA-I-BPB structure reveals a novel oligomeric conformation. This conformation is more energetically and conformationally stable than the native structure and the abolition of pharmacological activities by the ligand may be related to the oligomeric structural changes. A residue of the ;pancreatic' loop (Lys69), which is usually attributed as providing the anticoagulant effect, is in the dimeric interface of BthA-I-BPB, leading to a new hypothesis regarding the abolition of this activity by BPB. Structure of BthA-I complexed with p-bromophenacyl bromide: possible correlations with lack of pharmacological activity.,Magro AJ, Takeda AA, Soares AM, Fontes MR Acta Crystallogr D Biol Crystallogr. 2005 Dec;61(Pt 12):1670-7. Epub 2005, Nov 19. PMID:16301802[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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