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Characterization of 1,2-dibromoethane-degrading haloalkane dehalogenase from Bradyrhizobium japonicum USDA110

Paper ID Volume ID Publish Year Pages File Format Full-Text
17811 42697 2009 8 PDF Available
Title
Characterization of 1,2-dibromoethane-degrading haloalkane dehalogenase from Bradyrhizobium japonicum USDA110
Abstract

Haloalkane dehalogenases (DHAs, E.C. 3.8.1.5) are very promising biocatalytic tools for the bioremediation of environmental pollutants which consists of haloalkanes. In the present work, we investigated the DHA from Bradyrhizobium japonicum USDA110 (BjDHA). The dehalogenase activity of B. japonicum USDA110 and RT-PCR analysis revealed that the BjDHA gene expression is induced by 1,2-dibromoethane (1,2-DBE) during the early exponential phase. The BjDHA gene was cloned, expressed in Escherichia coli BL21 (DE3) and characterized. The enzyme catalyzes the irreversible hydrolysis of a variety of haloalkanes to the corresponding alcohol, halide, and a hydrogen ion. The catalytic properties of the recombinant enzyme were investigated and the kinetic parameters (Km, kcat) for a number of substrates were determined. The results showed that the BjDHA displays wide substrate specificity towards haloalkanes and particular high activity towards 1,2-DBE. The enzyme has a different catalytic triad topology compared to the Xanthobacter haloalkane dehalogenase and is more similar to the Rhodococcus enzyme. In addition, consistent with its broad specificity, the BjDHA has a substantially larger and more polar active site cavity compared to the Xanthobacter and Rhodococcus enzymes and as a consequence, BjDHA is able to dehalogenate longer and polar compounds. These properties make this enzyme very promising bioremediation tool for environmental applications.

Keywords
BCH, bromocyclohexane; 1,10-BD, 1,10-bromodecanoate; BjDHA, Bradyrhizobium japonicum USDA110 dehalogenase; DHA, dehalogenase; 1,2-DBE, 1,2-dibromoethane; 1,2-DBP, 1,2-dibromopropane; IPTG, isopropyl-β-d-thiogalactopyranoside; PAGE, polyacryamide gel elect
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Characterization of 1,2-dibromoethane-degrading haloalkane dehalogenase from Bradyrhizobium japonicum USDA110
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Publisher
Database: Elsevier - ScienceDirect
Journal: Enzyme and Microbial Technology - Volume 45, Issue 5, 5 November 2009, Pages 397–404
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us