Download MendeleyCrystal structure of the catalytic domain of the chemotaxis receptor methylesterase, CheB.
West, A.H., Martinez-Hackert, E., Stock, A.M.(1995) J Mol Biol 250: 276-290
- PubMed: 7608974
- DOI: https://doi.org/10.1006/jmbi.1995.0376
- Primary Citation of Related Structures:
1CHD - PubMed Abstract:
Signaling activity of bacterial chemotaxis transmembrane receptors is modulated by reversible covalent modification of specific receptor glutamate residues. The level of receptor methylation results from the activities of a specific S-adenosylmethionine-dependent methyltransferase, CheR, and the CheB methylesterase, which catalyzes hydrolysis of receptor glutamine or methylglutamate side-chains to glutamic acid. The CheB methylesterase belongs to a large family of response regulator proteins in which N-terminal regulatory domains control the activities of C-terminal effector domains. The crystal structure of the catalytic domain of the Salmonella typhimurium CheB methylesterase has been determined at 1.75 A resolution. The domain has a modified, doubly wound alpha/beta fold in which one of the helices is replaced by an anti-parallel beta-hairpin. Previous biochemical and mutagenesis data, suggest that the methylester hydrolysis catalyzed by CheB proceeds through a mechanism involving a serine nucleophile. The methylesterase active site is tentatively identified as a cleft at the C-terminal edge of the beta-sheet containing residues Ser164, His190 and Asp286. The three-dimensional fold, and the arrangement of residues within the catalytic triad distinguishes the CheB methylesterase from any previously described serine protease or serine hydrolase.
Organizational Affiliation:
Department of Biochemistry, University of Medicine and Dentistry, New Jersey-Robert Wood Johnson Medical School,Piscataway USA.
