Bailey D, Carpenter E P, Coker A, Coker S, Read J, Jones A T, Erskine P, Aguilar C F, Badasso M, Toldo L, Rippmann F, Sanz-Aparicio J, Albert A, Blundell T L, Roberts N B, Wood S P, Cooper J B
Incisive Media, 32-34 Broadwick Street, London W1A 2HG, England.
Acta Crystallogr D Biol Crystallogr. 2012 May;68(Pt 5):541-52. doi: 10.1107/S0907444912004817. Epub 2012 Apr 17.
The analysis reported here describes detailed structural studies of endothiapepsin (the aspartic proteinase from Endothia parasitica), with and without bound inhibitors, and human pepsin 3b. Comparison of multiple crystal structures of members of the aspartic proteinase family has revealed small but significant differences in domain orientation in different crystal forms. In this paper, it is shown that these differences in domain orientation do not necessarily correlate with the presence or absence of bound inhibitors, but appear to stem at least partly from crystal contacts mediated by sulfate ions. However, since the same inherent flexibility of the structure is observed for other enzymes in this family such as human pepsin, the native structure of which is also reported here, the observed domain movements may well have implications for the mechanism of catalysis.
本文报道的分析描述了对寄生内座壳天冬氨酸蛋白酶（来自寄生内座壳的天冬氨酸蛋白酶）在有和没有结合抑制剂情况下以及人胃蛋白酶3b的详细结构研究。天冬氨酸蛋白酶家族成员的多个晶体结构比较显示，不同晶体形式中结构域取向存在微小但显著的差异。本文表明，这些结构域取向的差异不一定与结合抑制剂的存在与否相关，而是似乎至少部分源于硫酸根离子介导的晶体接触。然而，由于在该家族的其他酶（如人胃蛋白酶，本文也报道了其天然结构）中观察到相同的结构固有灵活性，所观察到的结构域移动很可能对催化机制有影响。
