2had

From Proteopedia

Revision as of 09:31, 21 November 2007

CRYSTAL STRUCTURE OF HALOALKANE DEHALOGENASE: AN ENZYME TO DETOXIFY HALOGENATED ALKANES

Overview

Haloalkane dehalogenase from Xanthobacter autotrophicus GJ10 converts, 1-haloalkanes to the corresponding alcohols and halide ions with water as, the sole cosubstrate and without any need for oxygen or cofactors. The, three-dimensional structure has been determined by multiple isomorphous, replacement techniques using three heavy atom derivatives. The structure, has been refined at 2.4 A resolution to an R-factor of 17.9%. The, monomeric enzyme is a spherical molecule and is composed to two domains:, domain I has an alpha/beta type structure with a central eight-stranded, mainly parallel beta-sheet. Domain II lies like a cap on top of domain I, and consists of alpha-helices connected by loops. Except for the cap, domain the structure resembles that of the dienelactone hydrolase in spite, of any significant sequence homology. The putative active site is, completely buried in an internal hydrophobic cavity which is located, between the two domains. From the analysis of the structure it is, suggested that Asp124 is the nucleophilic residue essential for the, catalysis. It interacts with His289 which is hydrogen-bonded to Asp260.

About this Structure

2HAD is a Single protein structure of sequence from Xanthobacter autotrophicus. Full crystallographic information is available from OCA.

Reference

Crystal structure of haloalkane dehalogenase: an enzyme to detoxify halogenated alkanes., Franken SM, Rozeboom HJ, Kalk KH, Dijkstra BW, EMBO J. 1991 Jun;10(6):1297-302. PMID:2026135

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