2v7b

From Proteopedia

Revision as of 08:50, 3 February 2008

CRYSTAL STRUCTURES OF A BENZOATE COA LIGASE FROM BURKHOLDERIA XENOVORANS LB400

Overview

Xenobiotic aromatic compounds represent one of the most significant, classes of environmental pollutants. A novel benzoate oxidation (box), pathway has been identified recently in Burkholderia xenovorans LB400, (referred to simply as LB400) that is capable of assimilating benzoate and, intimately tied to the degradation of polychlorinated biphenyls (PCBs)., The box pathway in LB400 is present in two paralogous copies (box(M) and, box(C)) and encodes eight enzymes with the first committed step catalyzed, by benzoate CoA ligase (BCL). As a first step towards delineating the, biochemical role of the box pathway in LB400, we have carried out, functional studies of the paralogous BCL enzymes (BCL(M) and BCL(C)) with, 20 different putative substrates. We have established a structural, rationale for the observed substrate specificities on the basis of a 1.84, A crystal structure of BCL(M) in complex with benzoate. These data show, that, while BCL(M) and BCL(C) display similar overall substrate, specificities, BCL(M) is significantly more active towards benzoate and, 2-aminobenzoate with tighter binding (K(m)) and a faster reaction rate, (V(max)). Despite these clear functional differences, the residues that, define the substrate-binding site in BCL(M) are completely conserved in, BCL(C), suggesting that second shell residues may play a significant role, in substrate recognition and catalysis. Furthermore, comparison of the, active site of BCL(M) with the recently solved structures of, 4-chlorobenzoate CoA ligase and 2, 3-dihydroxybenzoate CoA ligase offers, additional insight into the molecular features that mediate substrate, binding in adenylate-forming enzymes. This study provides the first, biochemical characterization of a Box enzyme from LB400 and the first, structural characterization of a Box enzyme from any organism, and further, substantiates the concept of distinct roles for the two paralogous box, pathways in LB400.

About this Structure

2V7B is a Single protein structure of sequence from Burkholderia xenovorans with as ligand. Active as Benzoate--CoA ligase, with EC number 6.2.1.25 Known structural/functional Site: . Full crystallographic information is available from OCA.

Reference

Biochemical and Structural Characterization of the Paralogous Benzoate CoA Ligases from Burkholderia xenovorans LB400: Defining the Entry Point into the Novel Benzoate Oxidation (box) Pathway., Bains J, Boulanger MJ, J Mol Biol. 2007 Aug 19;. PMID:17884091

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