【作者】 望超； 王锋； 李梅； 桂璐璐； 张季平； 常文瑞；

【Author】 Chao Wang. Feng Wang, Mei Li, Lulu Gui, Jiping Zhang and Wenrui Chang Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101 stanley@tnoon.ibp.ac.cn

【机构】 中国科学院北京生物物理研究所；

【摘要】 <正> 蚯蚓纤溶酶组分A(EFE-a)具有弹性蛋白酶S1口袋,却可以水解多种底物,表现出广泛的底物专一性。基于计算机模拟,前期的结构测定工作认为EFE-a在Val217后四个残基的插入赋予其广泛的底物专一性。为验证模拟结果的正确性,阐明其广泛底物专一性的真正原因,我们在1.8A分辨率对2.3A的EFE-a更多还原

【Abstract】 Earthworm Fibrinolytic Enzyme Component A (EFE-a) possesses S1-pocket, which is typical for an elastase-like enzyme, but still could hydrolyze varieties of substrates, exhibits wide substrate specificity. Former structure studies suggested that the four-residue insertion after Val217 endowed EFE-a with this specificity. Based on the native crystal structure at the resolution of 2.3A, we improved the native crystal structure to 1.8A and determined its complex structure with the inhibitor Meo-Suc-Ala-Ala-Pro-Val-CMK at the resolution of 1.9 A. The final structures showed that: (1) EFE-a possesses multi substrate-binding sites interacting with the substrates; (2) significant conformation adjustment has taken place at two loops binding to the N-terminal of the substrates, which enhanced the interaction between the enzyme and the substrates. Those made the substrate-specificity of EFE-a less dependent on the property of its S1-pocket, and endowed the enzyme with the ability of hydrolyzing chymotrypsin-specific substrates and even trypsin-specific substrates.更多还原