The Three-dimensional Structure of 4-Hydroxybenzoyl-CoA Thioesterase from Pseudomonas sp. Strain CBS-3

• Published in: The Journal of biological chemistry 1998-12, Vol.273 (50), p.33572-33579
• Main Authors: Benning, M M, Wesenberg, G, Liu, R, Taylor, K L, Dunaway-Mariano, D, Holden, H M
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Aspartic Acid - chemistry; Aspartic Acid - metabolism; Binding Sites; Catalysis; Crystallography, X-Ray; Models, Molecular; Molecular Sequence Data; Protein Conformation; Pseudomonas; Pseudomonas - enzymology; Sequence Homology, Amino Acid; Thiolester Hydrolases - chemistry; Thiolester Hydrolases - metabolism
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.273.50.33572

The soil-dwelling microbe, Pseudomonas sp. strain CBS-3, has attracted recent attention due to its ability to survive on 4-chlorobenzoate as its sole carbon source. The biochemical pathway by which this organism converts 4-chlorobenzoate to 4-hydroxybenzoate consists of three enzymes: 4-chlorobenzoyl-CoA ligase, 4-chlorobenzoyl-CoA dehalogenase, and 4-hydroxybenzoyl-CoA thioesterase. Here we describe the three-dimensional structure of the thioesterase determined to 2.0-Å resolution. Each subunit of the homotetramer is characterized by a five-stranded anti-parallel β-sheet and three major α-helices. While previous amino acid sequence analyses failed to reveal any similarity between this thioesterase and other known proteins, the results from this study clearly demonstrate that the molecular architecture of 4-hydroxybenzoyl-CoA thioesterase is topologically equivalent to that observed for β-hydroxydecanoyl thiol ester dehydrase from Escherichia coli . On the basis of the structural similarity between these two enzymes, the active site of the thioesterase has been identified and a catalytic mechanism proposed.