1a2o
STRUCTURAL BASIS FOR METHYLESTERASE CHEB REGULATION BY A PHOSPHORYLATION-ACTIVATED DOMAIN
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OverviewOverview
We report the x-ray crystal structure of the methylesterase CheB, a, phosphorylation-activated response regulator involved in reversible, modification of bacterial chemotaxis receptors. Methylesterase CheB and, methyltransferase CheR modulate signaling output of the chemotaxis, receptors by controlling the level of receptor methylation. The structure, of CheB, which consists of an N-terminal regulatory domain and a, C-terminal catalytic domain joined by a linker, was solved by molecular, replacement methods using independent search models for the two domains., In unphosphorylated CheB, the N-terminal domain packs against the active, site of the C-terminal domain and thus inhibits methylesterase activity by, directly restricting access to the active site. We propose that, phosphorylation of CheB induces a conformational change in the regulatory, domain that disrupts the domain interface, resulting in a repositioning of, the domains and allowing access to the active site. Structural similarity, between the two companion receptor modification enzymes, CheB and CheR, suggests an evolutionary and/or functional relationship. Specifically, the, phosphorylated N-terminal domain of CheB may facilitate interaction with, the receptors, similar to the postulated role of the N-terminal domain of, CheR. Examination of surfaces in the N-terminal regulatory domain of CheB, suggests that despite a common fold throughout the response regulator, family, surfaces used for protein-protein interactions differ, significantly. Comparison between CheB and other response regulators, indicates that analogous surfaces are used for different functions and, conversely, similar functions are mediated by different molecular, surfaces.
About this StructureAbout this Structure
1A2O is a Single protein structure of sequence from Salmonella typhimurium. Active as Protein-glutamate methylesterase, with EC number 3.1.1.61 Structure known Active Sites: ESE and PON. Full crystallographic information is available from OCA.
ReferenceReference
Structural basis for methylesterase CheB regulation by a phosphorylation-activated domain., Djordjevic S, Goudreau PN, Xu Q, Stock AM, West AH, Proc Natl Acad Sci U S A. 1998 Feb 17;95(4):1381-6. PMID:9465023
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