X-ray analyses of aspartic proteinases. IV. Structure and refinement at 2.2 A resolution of bovine chymosin.
X-ray analyses of aspartic proteinases. IV. Structure and refinement at 2.2 A resolution of bovine chymosin.
复制标题
天冬氨酸蛋白酶的 X 射线分析。
DOI：
10.1016/0022-2836(91)90934-x
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发表时间：
1991
影响因子：
5.6
通讯作者：
N. Andreeva
中科院分区：
文献类型：
--
作者：
M. Newman;M. Safro;C. Frazão;G. Khan;A. Zdanov;I. Tickle;T. Blundell;N. Andreeva
采用分子置换技术对胃粘膜天冬氨酸蛋白酶小牛凝乳酶（EC 3.4.23.3）的结构进行了解析。我们描述了使用不同的搜索模型的基础上远亲的真菌天冬氨酸蛋白酶和调查的影响，只使用结构保守的区域。在2.2 μ m的分辨率下，晶体学R因子为17%，估计坐标误差为0.21 μ m。总共有136个水分子被定位，其中8个是内部的。凝乳酶的结构类似于胃蛋白酶和其他天冬氨酸蛋白酶的结构。然而，活性位点的“瓣”，特别是Tyr 75（胃蛋白酶编号），有相当大的重排，它形成了特异性口袋S1和S′1的一部分。这可能是晶体堆积的结果。底物结合裂缝边缘的静电相互作用似乎是凝乳酶对天然底物κ-酪蛋白的限制性蛋白水解的原因。不变的残基的本地环境进行检查，表明结构约束和侧链氢键可以发挥重要作用，在特定的氨基酸的保护。
The structure of calf chymosin (EC 3.4.23.3), the aspartic proteinase from the gastric mucosa, was solved using the technique of molecular replacement. We describe the use of different search models based on distantly related fungal aspartic proteinases and investigate the effect of using only structurally conserved regions. The structure has been refined to a crystallographicR-factor of 17% at 2.2Åresolution with an estimated co-ordinate error of 0.21Å. In all, 136 water molecules have been located of which eight are internal. The structure of chymosin resembles that of pepsin and other aspartic proteinases. However, there is a considerable rearrangement of the active-site “flap” and, in particular, Tyr75 (pepsin numbering), which forms part of the specificity pockets S1and S′1. This is probably a consequence of crystal packing. Electrostatic interactions on the edge of the substrate binding cleft appear to account for the restricted proteolysis of the natural substrate κ-casein by chymosin. The local environment of invariant residues is examined, showing that structural constraints and side-chain hydrogen bonding can play an important role in the conservation of particular amino acids.
中华根霉天冬氨酸蛋白酶的 1.8 A 分辨率的结构和精修。
影响因子：
5.6
作者：
Suguna,K;Bott,RR;Padlan,EA;Subramanian,E;Sheriff,S;Cohen,GH;Davies,DR
通讯作者：
Davies,DR
影响因子：
56.9
作者：
WLODAWER, A;MILLER, M;KENT, SBH
通讯作者：
KENT, SBH