1A2O

STRUCTURAL BASIS FOR METHYLESTERASE CHEB REGULATION BY A PHOSPHORYLATION-ACTIVATED DOMAIN

Summary for 1A2O

• Entry DOI: 10.2210/pdb1a2o/pdb
• Descriptor: CHEB METHYLESTERASE (2 entities in total)
• Functional Keywords: bacterial chemotaxis, adaptation, serine hydrolase
• Biological source: Salmonella typhimurium
• Cellular location: Cytoplasm: P04042
• Total number of polymer chains: 2
• Total formula weight: 75197.70

Authors

Djordjevic, S.,Goudreau, P.N.,Xu, Q.,Stock, A.M.,West, A.H. (deposition date: 1998-01-06, release date: 1998-04-29, Last modification date: 2024-05-22)

Primary citation

Djordjevic, S.,Goudreau, P.N.,Xu, Q.,Stock, A.M.,West, A.H.
Structural basis for methylesterase CheB regulation by a phosphorylation-activated domain.
Proc.Natl.Acad.Sci.USA, 95:1381-1386, 1998

PubMed Abstract: 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.

PubMed: 9465023
DOI: 10.1073/pnas.95.4.1381

Experimental method

X-RAY DIFFRACTION (2.4 Å)