The molecular basis of thrombin allostery revealed by a 1.8 Å structure of the "slow" form
The molecular basis of thrombin allostery revealed by a 1.8 Å structure of the "slow" form
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DOI：
10.1016/s0969-2126(03)00049-2
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发表时间：
2003-04-01
期刊：
影响因子：
5.7
通讯作者：
Esmon, CT
中科院分区：
文献类型：
--
作者：
Huntington, JA;Esmon, CT
凝血酶参与其自身的正反馈循环和负反馈循环，其变构状态有助于确定止血平衡。在这里，我们展示了 S195A 凝血酶的 1.8 埃晶体结构，其具有两种构象状态：活性位点占据和活性位点游离。活性位点占据形式显示了凝血酶如何容纳底物，例如蛋白C。无活性位点形式处于先前未观察到的凝血酶的闭合构象，它满足所谓“慢”形式的所有条件。揭示了变构机制，该机制依赖于 Cys168 和 182 与芳香族残基 Phe227、Trp215 和 Trp60d 之间二硫键的协同运动。这些残基构成变构开关，通过钠结合直接翻转，形成具有开放活性位点的快速形式。
Thrombin participates in its own positive and negative feedback loops, and its allosteric state helps determine the hemostatic balance. Here we present the 1.8 Angstrom crystallographic structure of S195A thrombin in two conformational states: active site occupied and active site free. The active site-occupied form shows how thrombin can accommodate substrates, such as protein C. The active site-free form is in a previously unobserved closed conformation of thrombin, which satisfies all the conditions of the so-called "slow" form. A mechanism of allostery is revealed, which relies on the concerted movement of the disulphide bond between Cys168 and 182 and aromatic residues Phe227, Trp215, and Trp60d. These residues constitute an allosteric switch, which is flipped directly through sodium binding, resulting in the fast form with an open active site.