Masuda S, Ohta T, Kaji K, Fox J W, Hayashi H, Araki S
Sugashima Marine Biological Laboratory, Graduate School of Science, Nagoya University, Toba, Mie 517-0004, Japan.
Biochem Biophys Res Commun. 2000 Nov 11;278(1):197-204. doi: 10.1006/bbrc.2000.3770.
Hemorrhagic snake venom induces apoptosis in vascular endothelial cells (VEC). In previous reports, we described the purification from crude venom of Crotalus atrox of two vascular apoptosis-inducing proteins (VAP1 and VAP2) that specifically induce apoptosis in vascular endothelial cells. We report here the cDNA cloning and characterization of VAP1. VAP1 cDNA encoded a protein with 610 amino acid residues. The amino acid sequence predicted from the cDNA indicated that VAP1 belongs to the metalloprotease/disintegrin family and that it is a multidomain polypeptide with a proprotein domain, a metalloprotease domain, a disintegrin-like domain, and a cysteine-rich domain. In the disintegrin-like domain, the sequence DECD replaces the RGD sequence that has frequently been found in such domains. We demonstrated that VAP1 has Zn(2+)-dependent metalloprotease activity and degrades fibrinogen. After incubation in the presence of either EDTA or EGTA, VAP1 was hardly able to degrade fibrinogen and to induce apoptosis in VEC. Our results indicated that VAP1 is a new type of snake venom metalloprotease/disintegrin and suggest that the metalloprotease activity of VAP1 might be involved in the induction of apoptosis by VAP1 in VEC.
出血性蛇毒可诱导血管内皮细胞（VEC）凋亡。在之前的报道中，我们描述了从粗制的墨西哥矛头蝮蛇毒中纯化出两种血管凋亡诱导蛋白（VAP1和VAP2），它们能特异性诱导血管内皮细胞凋亡。我们在此报告VAP1的cDNA克隆及特性。VAP1的cDNA编码一种含有610个氨基酸残基的蛋白质。根据cDNA预测的氨基酸序列表明，VAP1属于金属蛋白酶/解整合素家族，是一种具有前体蛋白结构域、金属蛋白酶结构域、解整合素样结构域和富含半胱氨酸结构域的多结构域多肽。在解整合素样结构域中，序列DECD取代了该结构域中常见的RGD序列。我们证明VAP1具有锌离子依赖性金属蛋白酶活性，并能降解纤维蛋白原。在EDTA或EGTA存在的情况下孵育后，VAP1几乎无法降解纤维蛋白原，也无法诱导VEC凋亡。我们的结果表明，VAP1是一种新型的蛇毒金属蛋白酶/解整合素，并提示VAP1的金属蛋白酶活性可能参与其在VEC中诱导凋亡的过程。
