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Cited 44 time in webofscience Cited 45 time in scopus
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Role of catalytic residues in enzymatic mechanisms of homologous ketosteroid isomerases

Title
Role of catalytic residues in enzymatic mechanisms of homologous ketosteroid isomerases
Authors
Oh, KSCha, SSKim, DHCho, HSHa, NCChoi, GLee, JYTarakeshwar, PSon, HSChoi, KYOh, BHKim, KS
POSTECH Authors
Choi, KYOh, BH
Date Issued
Jan-2000
Publisher
AMER CHEMICAL SOC
Abstract
Ketosteroid isomerase (KSI) is one of the most proficient enzymes catalyzing an allylic isomerization reaction at a diffusion-controlled rate. In this study of KSI, we have detailed the structures of its active site, the role of various catalytic residues, and have explained the origin of the its fast reactivity by carrying out a detailed investigation of the enzymatic reaction mechanism. This investigation included the X-ray determination of 15 crystal structures of two homologous enzymes in free and complexed states (with inhibitors) and extensive ab initio calculations of the interactions between the active sites and the reaction intermediates. The catalytic residues, through short strong hydrogen bonds, play the role of charge buffer to stabilize the negative charge built up on the intermediates in the course of the reaction. The hydrogen bond distances in the intermediate analogues are found to be about 0.2 Angstrom shorter in the product analogues both experimentally and theoretically.
Keywords
PUTIDA BIOTYPE-B; SITE-DIRECTED MUTAGENESIS; BARRIER HYDROGEN-BOND; DELTA(5)-3-KETOSTEROID ISOMERASE; DELTA-5-3-KETOSTEROID ISOMERASE; 3-OXO-DELTA(5)-STEROID ISOMERASE; PSEUDOMONAS-TESTOSTERONI; CRYSTAL-STRUCTURE; MUTANT; D38N
URI
http://oasis.postech.ac.kr/handle/2014.oak/19793
DOI
10.1021/BI001629H
ISSN
0006-2960
Article Type
Article
Citation
BIOCHEMISTRY, vol. 39, no. 45, page. 13891 - 13896, 2000-01
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 CHOI, KWAN YONG
Div of Integrative Biosci & Biotech
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