Crystal structure of the stromelysin catalytic domain at 2.0 Å resolution:: Inhibitor-induced conformational changes
Crystal structure of the stromelysin catalytic domain at 2.0 Å resolution:: Inhibitor-induced conformational changes
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DOI：
10.1006/jmbi.1999.3147
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发表时间：
1999-10-29
影响因子：
5.6
通讯作者：
Barnett, BL
中科院分区：
文献类型：
--
作者：
Chen, LY;Rydel, TJ;Barnett, BL
基质金属蛋白酶在骨关节炎、类风湿性关节炎和肿瘤侵袭等病理过程中起重要作用。基质溶解素是一种锌依赖性蛋白酶，属于基质金属蛋白酶家族。我们已经解决了截短的基质溶解素的活性未抑制形式和与异羟肟酸盐为基础的抑制剂的复合物的晶体结构。残基83-255的酶的催化结构域是活性片段。两个晶体学上独立的分子A和B在晶体中缔合为二聚体。每个分子中有三个α-螺旋和一个扭曲的五股β-折叠，以及一个催化Zn，一个结构Zn和三个结构Ca离子。溶基质素的活性位点位于一个大的疏水裂隙中。特别地，S1'特异性位点是深且高度疏水的空腔。作为我们基于结构的设计策略的一部分，通过扩散浸泡形成的异羟肟酸-膦酰胺型结合基质溶解素复合物的结构已经得到解决。我们观察到的最重要的特征是由Tyr 223触发的S1'腔中的通道诱导的构象变化。在未受抑制的酶结构中，Tyr 223完全覆盖S1'腔，而在复合物中，抑制剂的P1'基团取代Tyr 223以适合S1'腔。此外，Tyr 223的置换诱导了从残基222到残基231的整个环的主要构象变化。这一发现为Tyr 223在S1'腔中扮演守门人的角色提供了直接证据。另一个重要的分子间相互作用发生在分子A的活性位点，其中来自分子B的C-末端尾（残基251-255）插入。C-末端尾部与分子A的活性位点广泛相互作用，并且最后一个残基（Thr 255）作为第四配体与催化锌配位，非常像产物抑制剂。分子内C-末端锌的配位和构象变化对理解酶的构效关系具有重要意义。(C)北京：科学出版社.
Matrix metalloproteinases are believed to play an important role in pathological conditions such as osteoarthritis, rheumatoid arthritis and tumor invasion. Stromelysin is a zinc-dependent proteinase and a member of the matrix metalloproteinase family. We have solved the crystal structure of an active uninhibited form of truncated stromelysin and a complex with a hydroxamate-based inhibitor. The catalytic domain of the enzyme of residues 83-255 is an active fragment. Two crystallographically independent molecules, A and B, associate as a dimer in the crystals. There are three alpha-helices and one twisted, five-strand beta-sheet in each molecule, as well as one catalytic Zn, one structural Zn and three structural Ca ions. The active site: of stromelysin is located in a large, hydrophobic cleft. Ln particular, the S1' specificity site is a deep and highly hydrophobic cavity. The structure of a hydroxamate-phosphinamide-type inhibitor-bound stromelysin complex, formed by diffusion soaking, has been solved as part of our-structure-based design strategy. The most important feature we observed is an inhibitor-induced conformational change in the S1' cavity which is triggered by Tyr223. Ln the uninhibited enzyme structure, Tyr223 completely covers the S1' cavity, while in the complex, the P1' group of the inhibitor displaces the Tyr223 in order to fit into the S1' cavity. Furthermore, the displacement of Tyr223 induces a major conformational change: of the entire loop from residue 222 to residue 231. This finding provides direct evidence that Tyr223 plays the role of gatekeeper of the S1' cavity. Another important intermolecular interaction occurs at the active sit of molecule A, in which the C-terminal tail (residues 251-255) from molecule B inserts. The C-terminal tail interacts extensively with the active site of molecule A, and the last residue (Thr255) coordinated to the catalytic zinc as the fourth ligand, much like a product inhibitor would. The inhibitor-induced conformational change and the intermolecular C-terminal-zinc coordination are significant in understanding the structure-activity relationships of the enzyme. (C) 1999 Academic Press.