Three-dimensional structure of the complex of the Rhizopus chinensis carboxyl proteinase and pepstatin at 2.5-A resolution.
Three-dimensional structure of the complex of the Rhizopus chinensis carboxyl proteinase and pepstatin at 2.5-A resolution.
复制标题
中华根霉羧基蛋白酶和胃酶抑素复合物的三维结构，分辨率为 2.5 A。
作者：
R. Bott;E. Subramanian;D. Davies
本文用X射线衍射法分析了华根霉羧基蛋白酶与胃蛋白酶抑制剂复合物的三维结构。复合物的所得模型支持假设[Marciniszyn，J.，Hartsuck，J.A.，& Tang，J.（1976）J.Biol.Chem.251，7088-7094]，他汀（3-羟基-4-氨基-6-甲基庚酸）接近用于催化的过渡态的类似物。胃蛋白酶抑制剂结合酶的方式可以扩展到提供底物结合的模型和过渡态复合物的模型。这反过来又导致了一种基于一般酸碱催化而没有共价中间体的拟议作用机制。这些预测与使用几种羧基蛋白酶的动力学研究基本一致，这些研究与它们的序列同源性和它们共同的三维结构一起表明，这种机制可以外推到所有羧基蛋白酶。
An X-ray diffraction analysis has been carried out at 2.5-A resolution of the three-dimensional structure of the Rhizopus chinensis carboxyl proteinase complexed with pepstatin. The resulting model of the complex supports the hypothesis [Marciniszyn, J., Hartsuck, J.A., & Tang, J. (1976) J. Biol. Chem. 251, 7088-7094] that statine (3-hydroxy-4-amino-6-methylheptanoic acid) approaches an analogue of the transition state for catalysis. The way in which pepstatin binds to the enzyme can be extended to provide a model of substrate binding and a model of the transition-state complex. This in turn has led to a proposed mechanism of action based on general acid-base catalysis with no covalent intermediates. These predictions are in general agreement with kinetic studies using several carboxyl proteinases, which together with their sequence homology and their common three-dimensional structures suggest that this mechanism can be extrapolated to all carboxyl proteinases.