1ogx

From Proteopedia

Revision as of 11:48, 30 October 2007

HIGH RESOLUTION CRYSTAL STRUCTURE OF KETOSTEROID ISOMERASE MUTANT D40N(D38N, TI NUMBERING) FROM PSEUDOMONAS PUTIDA COMPLEXED WITH EQUILENIN AT 2.0 A RESOLUTION.

Overview

Delta(5)-3-Ketosteroid isomerase catalyzes cleavage and formation of a C-H, bond at a diffusion-controlled limit. By determining the crystal, structures of the enzyme in complex with each of three different, inhibitors and by nuclear magnetic resonance (NMR) spectroscopic, investigation, we evidenced the ionization of a hydroxyl group (pK(a), approximately 16.5) of an inhibitor, which forms a low barrier hydrogen, bond (LBHB) with a catalytic residue Tyr(14) (pK(a) approximately 11.5), and the protonation of the catalytic residue Asp(38) with pK(a) of, approximately 4.5 at pH 6.7 in the interaction with a carboxylate group of, an inhibitor. The perturbation of the pK(a) values in both cases arises, from the formation of favorable interactions between inhibitors and, catalytic residues. ... [(full description)]

About this Structure

1OGX is a [Single protein] structure of sequence from [Pseudomonas putida] with EQU as [ligand]. This structure superseeds the now removed PDB entry 1E3N. Active as [Steroid Delta-isomerase], with EC number [5.3.3.1]. Structure known Active Site: AC1. Full crystallographic information is available from [OCA].

Reference

Detection of large pKa perturbations of an inhibitor and a catalytic group at an enzyme active site, a mechanistic basis for catalytic power of many enzymes., Ha NC, Kim MS, Lee W, Choi KY, Oh BH, J Biol Chem. 2000 Dec 29;275(52):41100-6. PMID:11007792

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