The structure of an enzyme-product complex reveals the critical role of a terminal hydroxide nucleophile in the bacterial phosphotriesterase mechanism

被引：70

作者：

Jackson, C ^{[1
]}

Kim, HK ^{[1
]}

Carr, PD ^{[1
]}

Liu, JW ^{[1
]}

Ollis, DL ^{[1
]}

机构：

[1] Australian Natl Univ, Res Sch Chem, Canberra, ACT 0200, Australia

来源：

BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS | 2005年 / 1752卷 / 01期

基金：

澳大利亚研究理事会;

关键词：

phosphotriesterase; mechanism; binuclear; metalloenzyme; nucleophile;

D O I：

10.1016/j.bbapap.2005.06.008

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

A detailed understanding of the catalytic mechanism of enzymes is an important step toward improving their activity for use in biotechnology. In this paper, crystal soaking experiments and X-ray crystallography were used to analyse the mechanism of the Agrobacterium radiobacter phosphotriesterase, OpdA, an enzyme capable of detoxifying a broad range of organophosphate pesticides. The structures of OpdA complexed with ethylene glycol and the product of dimethoate hydrolysis, dimethyl thiophosphate, provide new details of the catalytic mechanism. These structures suggest that the attacking nucleophile is a terminally bound hydroxide, consistent with the catalytic mechanism of other binuclear metallophosphoesterases. In addition, a crystal structure with the potential substrate trimethyl phosphate bound non-productively demonstrates the importance of the active site cavity in orienting the substrate into an approximation of the transition state. (c) 2005 Elsevier B.V All rights reserved.

引用

页码：56 / 64

页数：9

共 29 条

[11] Reactivity of μ-hydroxodizinc(II) centers in enzymatic catalysis through model studies [J].