Fernandez Jorge H, Silva Carlos A, Assakura Marina T, Camargo Antonio C M, Serrano Solange M T
Laboratorio Especial de Toxinologia Aplicada and CAT/CEPID, Instituto Butantan, CEP 05503-900, Sao Paulo, Brazil.
Biochem Biophys Res Commun. 2005 Apr 8;329(2):457-64. doi: 10.1016/j.bbrc.2005.01.148.
Disintegrins are among the most potent antagonists of several integrins. A cDNA encoding a novel disintegrin, bothrostatin, was cloned from a Bothrops jararaca cDNA library. The precursor of bothrostatin contains a pro, a metalloproteinase, and an RGD-disintegrin domain. The disintegrin domain expressed in Escherichia coli showed high inhibitory activity on collagen-induced platelet aggregation (IC(50) of 12nM), and thus it can be used as a useful tool for studies of integrin-ligand interaction. Furthermore, we used the comparative modeling approach to obtain a model of the 3D structure of bothrostatin. Our results suggest that bothrostatin adopts a globular, closed structure in solution. The RGD motif is exposed to the solution by the loop formed by residues 45-59 and is very close to the C-terminal domain forming a finger-like structure. The proximity of the RGD loop and the C-terminal residues, which is maintained by the Cys47-Cys66 bond, suggests that the C-terminal residues are involved in the ability of bothrostatin to interact with its ligands.
去整合素是几种整合素最有效的拮抗剂之一。从巴西矛头蝮蛇的cDNA文库中克隆出一个编码新型去整合素双斑蝰素的cDNA。双斑蝰素的前体包含一个原结构域、一个金属蛋白酶结构域和一个RGD-去整合素结构域。在大肠杆菌中表达的去整合素结构域对胶原诱导的血小板聚集表现出高抑制活性（IC50为12nM），因此它可作为研究整合素-配体相互作用的有用工具。此外，我们采用比较建模方法获得了双斑蝰素的三维结构模型。我们的结果表明，双斑蝰素在溶液中呈球状、封闭结构。RGD基序通过45-59位残基形成的环暴露于溶液中，并且非常靠近形成指状结构的C末端结构域。由Cys47-Cys66键维持的RGD环与C末端残基的接近性表明，C末端残基参与了双斑蝰素与其配体相互作用的能力。
