Convulxin, a potent platelet-aggregating protein from Crotalus durissus terrificus venom, specifically binds to platelets
Convulxin, a potent platelet-aggregating protein from Crotalus durissus terrificus venom, specifically binds to platelets
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DOI：
10.1016/s0041-0101(97)00021-4
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发表时间：
1997-08-01
期刊：
影响因子：
2.8
通讯作者：
Bon, C
中科院分区：
文献类型：
--
作者：
Francischetti, IMB;Saliou, B;Bon, C
Convulxin 是一种来自响尾蛇毒液的非常有效的聚集蛋白，通过新程序纯化，并证实了其异二聚体结构 α(3) beta(3)。通过Edman降解测定惊厥蛋白亚基的多肽N端序列。它们与来自Bothrops jararaca毒液的botrocetin和来自Crotalus atrox毒液的响尾蛇凝集素非常相似并且看起来同源，两者都属于C型凝集素家族。 I-125 标记的 convulxin 与血小板的结合也在平衡条件下进行了分析。这些研究表明，convulxin 在少数结合位点（每个细胞 1000 个结合位点）上以高亲和力 (K-d = 30 pM) 与血小板结合。惊旋蛋白的高亲和力结合似乎对血小板具有特异性，因为在其他细胞类型（例如中性粒细胞和红细胞）上没有观察到它。此外，惊厥蛋白与血小板膜的高亲和力结合不受α-凝血酶、纤维蛋白原、胶原蛋白、层粘连蛋白结合抑制剂、RGDS肽、二磷酸腺苷、血小板激活因子乙醚、血清素或肾上腺素的抑制。这与最近观察到的惊旋蛋白激活血小板部分由磷脂酶 C 介导并且还涉及其他机制的观察结果一起，表明惊旋蛋白可能与尚未表征的特定血小板受体蛋白相互作用。 (C) 1997 爱思唯尔科学有限公司。
Convulxin, a very potent aggregating protein from rattlesnake venom, was purified by a new procedure and its heterodimeric structure alpha(3) beta(3) was confirmed. The polypeptide N-terminal sequences of convulxin subunits were determined by Edman degradation. They are very similar and appear homologous to botrocetin from Bothrops jararaca venom and to rattlesnake lectin from Crotalus atrox venom, both being classified among the C-type lectin family. The binding of I-125-labelled convulxin to blood platelets has also been analysed under equilibrium conditions, These studies indicated that convulxin binds to platelets with a high affinity (K-d = 30 pM) on a small number of binding sites (1000 binding sites per cell). The high-affinity binding of convulxin appears specific to platelets, since it is not observed on other cell types such as neutrophils and erythrocytes. Also, the high-affinity binding of convulxin to membranes platelet is not inhibited by alpha-thrombin, fibrinogen, collagen, laminin binding inhibitor, RGDS peptide, adenosine diphosphate, platelet-activating factor-acether, serotonin or epinephrine. This, together with the recent observation that platelet activation by convulxin is partially mediated by phospholipase C and involves other mechanisms as well, indicates that convulxin may interact with a specific platelet acceptor (receptor) protein which has yet to be characterized. (C) 1997 Elsevier Science Ltd.