1g42

From Proteopedia

Revision as of 13:34, 20 November 2007

STRUCTURE OF 1,3,4,6-TETRACHLORO-1,4-CYCLOHEXADIENE HYDROLASE (LINB) FROM SPHINGOMONAS PAUCIMOBILIS COMPLEXED WITH 1,2-DICHLOROPROPANE

Overview

The hydrolysis of haloalkanes to their corresponding alcohols and, inorganic halides is catalyzed by alpha/beta-hydrolases called haloalkane, dehalogenases. The study of haloalkane dehalogenases is vital for the, development of these enzymes if they are to be utilized for bioremediation, of organohalide-contaminated industrial waste. We report the kinetic and, structural analysis of the haloalkane dehalogenase from Sphingomonas, paucimobilis UT26 (LinB) in complex with each of 1,2-dichloroethane and, 1,2-dichloropropane and the reaction product of 1-chlorobutane turnover., Activity studies showed very weak but detectable activity of LinB with, 1,2-dichloroethane [0.012 nmol s(-1) (mg of enzyme)(-1)] and, 1,2-dichloropropane [0.027 nmol s(-1) (mg of enzyme)(-1)]. These, activities are much weaker compared, for example, to the activity of LinB, with 1-chlorobutane [68.2 nmol s(-1) (mg of enzyme)(-1)]. Inhibition, analysis reveals that both 1,2-dichloroethane and 1,2-dichloropropane act, as simple competitive inhibitors of the substrate 1-chlorobutane and that, 1,2-dichloroethane binds to LinB with lower affinity than, 1,2-dichloropropane. Docking calculations on the enzyme in the absence of, active site water molecules and halide ions confirm that these compounds, could bind productively. However, when these moieties were included in the, calculations, they bound in a manner similar to that observed in the, crystal structure. These data provide an explanation for the low activity, of LinB with small, chlorinated alkanes and show the importance of active, site water molecules and reaction products in molecular docking.

About this Structure

1G42 is a Single protein structure of sequence from Sphingomonas paucimobilis with ACT, CA, CL and CP2 as ligands. Full crystallographic information is available from OCA.

Reference

Exploring the structure and activity of haloalkane dehalogenase from Sphingomonas paucimobilis UT26: evidence for product- and water-mediated inhibition., Oakley AJ, Prokop Z, Bohac M, Kmunicek J, Jedlicka T, Monincova M, Kuta-Smatanova I, Nagata Y, Damborsky J, Wilce MC, Biochemistry. 2002 Apr 16;41(15):4847-55. PMID:11939779

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