Identification of critical residues on thrombin mediating its interaction with fibrin
Identification of critical residues on thrombin mediating its interaction with fibrin
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DOI：
10.1055/s-0037-1616750
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发表时间：
2001-12-01
影响因子：
6.7
通讯作者：
Leung, LLK
中科院分区：
文献类型：
--
作者：
Hall, SW;Gibbs, CS;Leung, LLK
凝血酶与纤维蛋白的结合可能在将凝血酶定位于血管损伤部位中是重要的。然而，纤维蛋白结合的凝血酶保持其与纤维蛋白原的催化活性，并且在某些条件下可能是促血栓形成的。52个纯化的凝血酶突变体的集合用于鉴定介导凝血酶-纤维蛋白相互作用的那些残基。比较纤维蛋白原凝血活性与纤维蛋白结合活性，鉴定了20个参与纤维蛋白原识别的残基，其中4个残基在纤维蛋白结合中很重要（Lys（65）、His（66）、Tyr（71）、Arg（73））。没有发现具有正常凝血活性和纤维蛋白结合缺陷的突变体，表明这两种性质不容易分离。结合这些残基的DNA凝血酶适体能够抑制凝血酶-纤维蛋白相互作用，并取代已经结合的凝血酶。凝血酶上的这些纤维蛋白结合残基的映射揭示了它们位于外位点I内。并且包含在纤维蛋白原识别中重要的残基的子集。
Thrombin binding to fibrin may be important in localizing thrombin to the site of vascular injury. However, fibrin-bound thrombin retains its catalytic activity tow ard fibrinogen, and may be prothrombotic under certain conditions. A collection of 52 purified thrombin mutants was used to identify those residues mediating the thrombin-fibrin interaction. Comparison of fibrinogen clotting activity with fibrin binding activity identified twenty residues involved in fibrinogen recognition with four of these residues important in fibrin binding (Lys(65), His(66), Tyr(71), Arg(73)). No mutant was identified with normal clotting activity and deficient fibrin binding, suggesting that these two properties are not readily dissociable, A DNA thrombin aptamer that binds to these residues was able to inhibit the thrombin-fibrin interaction, and displace thrombin that was already bound. Mapping of these fibrin-binding residues on thrombin revealed that they are localized within exosite I. and comprise a subset of the residues important in fibrinogen recognition.