The BH1999 Protein of Bacillus halodurans C-125 Is Gentisyl-Coenzyme A Thioesterase

AUTOR(ES)

Zhuang, Zhihao

FONTE

American Society for Microbiology

RESUMO

In this study, we have shown that recombinant BH1999 from Bacillus halodurans catalyzes the hydrolysis of gentisyl coenzyme A (CoA) (2,5-dihydroxybenzoyl-coenzyme A) at physiological pH with a kcat/Km of 1.6 × 106 M−1 s−1 and the hydrolysis of 3-hydroxybenzoyl-CoA with a kcat/Km of 3.0 × 105 M−1 s−1. All other acyl-CoA thioesters tested had low or no substrate activity. The BH1999 gene is juxtaposed with a gene cluster that contains genes believed to function in gentisate oxidative degradation. It is hypothesized that BH1999 functions as a gentisyl-CoA thioesterase. Gentisyl-CoA thioesterase shares the backbone fold and the use of an active site aspartate residue to mediate catalysis with the 4-hydroxybenzoyl-CoA thioesterase of the hotdog fold enzyme superfamily. A comparative study of these two enzymes showed that they differ greatly in the rate contribution made by the catalytic aspartate, in the pH dependence of catalysis, and in substrate specificity.

Documentos Relacionados

• Identification and Distribution of New Insertion Sequences in the Genome of Alkaliphilic Bacillus halodurans C-125
• Molecular cloning and expression of the xylanase gene of alkalophilic Bacillus sp. strain C-125 in Escherichia coli.
• Contribution of the Cell Wall Component Teichuronopeptide to pH Homeostasis and Alkaliphily in the Alkaliphile Bacillus lentus C-125
• DNA sequences required for the alkalophily of Bacillus sp. strain C-125 are located close together on its chromosomal DNA.
• Characterization of the 4-Hydroxybenzoyl-Coenzyme A Thioesterase from Arthrobacter sp. Strain SU