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首页> 外文期刊>Archives of Biochemistry and Biophysics >Structural and functional characterization of BnSP-7, a Lys49 myotoxic phospholipase A(2) homologue from Bothrops neuwiedi pauloensis Venom
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Structural and functional characterization of BnSP-7, a Lys49 myotoxic phospholipase A(2) homologue from Bothrops neuwiedi pauloensis Venom

机译：结构和功能表征的BnSP-7，Byrops neuwiedi pauloensis毒液的Lys49肌毒性磷脂酶A（2）同源物

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摘要

BnSP-7, a Lys49 myotoxic phospholipase A, homologue from Bothrops neuwiedi pauloensis venom, was structurally and functionally characterized. Several biological activities were assayed and compared with those of the chemically modified toxin involving specific amino acid residues, The cDNA produced from the total RNA by RT-PCR contained approximately 400 bp which codified its 121 amino acid residues with a calculated pi and molecular weight of 8.9 and 13,727, respectively. Its amino acid sequence showed strong similarities with several Lys49 phospholipase A, homologues from other Bothrops sp, venoms. By affinity chromatography and gel diffusion, it was demonstrated that heparin formed a complex with BnSP-7, held at least in part by electrostatic interactions. BnSP-7 displayed bactericidal activity and promoted the blockage of the neuromuscular contraction of the chick, biventer cervicis muscle. In addition to its in vivo myotoxic and edema-inducing activity, it disrupted artificial membranes, Both BnSP-7 and the crude venom released creatine kinase from the mouse gastrocnemius muscle and induced the development of a dose-dependent edema. His, Tyr, and Lys residues of the toxin were chemically modified by 4-bromophhenacyl bromide (BPB), 2-nitrobenzenesulfonyl fluoride (NBSF), and acetic anhydride (AA), respectively. Cleavage of its N-terminal octapeptide was achieved with cyanogen bromide (CNBr), The bactericidal action of BnSP-7 on Escherichia coli was almost completely abolished by acetylation or cleavage of the N-terminal octapeptide, The neuromuscular effect induced by BnSP-7 was completely inhibited by heparin, BPB, acetylation, and CNBr treatment. The creatine kinase releasing and edema-inducing effects were partially inhibited by heparin or modification by BPB and almost completely abolished by acetylation or cleavage of the N-terminal octapeptide, The rupture of liposomes by BnSP-7 and crude venom was dose and temperature dependent. Incubation of BnSP-7 with EDTA did not change this effect, suggesting a Ca2+-independent membrane lytic activity. BnSP-7 cross-reacted with antibodies raised against B. moojeni (MjTX-II), B. jararacussu (BthTX-I), and B. asper (Basp-II) myotoxins as well as against the C-terminal peptide (residues 115-129) from Basp-II. (C) 2000 Academic Press. [References: 44]
机译：BnSP-7，一种Lys49肌毒性磷脂酶A，来自鲍氏新芽鲍鱼毒液的同源物，在结构和功能上得到了表征。测定了几种生物活性并将其与涉及特定氨基酸残基的化学修饰毒素的生物学活性进行比较。通过RT-PCR从总RNA产生的cDNA包含约400 bp，将其121个氨基酸残基编码为pI和分子量分别为8.9和13,727。它的氨基酸序列与几种Lys49磷脂酶A（与其他Bothrops sp。毒液的同系物）同源。通过亲和层析和凝胶扩散，证明肝素与BnSP-7形成复合物，其至少部分地通过静电相互作用保持。 BnSP-7表现出杀菌活性，并促进了雏鸡宫颈颈肌神经肌肉收缩的阻滞。除了其体内的肌毒性和水肿诱导活性外，它还破坏了人造膜，BnSP-7和粗毒都从小鼠腓肠肌释放了肌酸激酶，并诱导了剂量依赖性水肿的发展。毒素的His，Tyr和Lys残基分别通过4-溴苯乙酰溴（BPB），2-硝基苯磺酰氟（NBSF）和乙酸酐（AA）进行了化学修饰。用溴化氰（CNBr）裂解其N端八肽，通过乙酰化或裂解N端八肽几乎完全消除了BnSP-7对大肠杆菌的杀菌作用，BnSP-7诱导的神经肌肉作用为完全被肝素，BPB，乙酰化和CNBr处理所抑制。肝素或BPB修饰可部分抑制肌酸激酶的释放和水肿诱导作用，而N端八肽的乙酰化或裂解则几乎完全消除肌酸激酶的释放.BnSP-7和粗毒液对脂质体的破坏取决于剂量和温度。将BnSP-7与EDTA一起孵育不会改变这种作用，表明不依赖Ca2 +的膜裂解活性。 BnSP-7与针对moojeni（MjTX-II），jararacussu（BthTX-I）和B.asper（Basp-II）肌毒素以及C末端肽（残基115）产生的抗体发生交叉反应-129）来自Basp-II。 （C）2000年学术出版社。 [参考：44]

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