The structures of T87I phosphono-CheY and T87I/Y106W phosphono-CheY help to explain their binding affinities to the FliM and CheZ peptides
- UNC
CheY is a response regulator in bacterial chemotaxis. Escherichia coli CheY mutants T87I and T87I/Y106W CheY are phosphorylatable on Asp57 but unable to generate clockwise rotation of the flagella. To understand this phenotype in terms of structure, stable analogs of the two CheY-P mutants were synthesized: T87I phosphono-CheY and T87I phosphono-CheY. Dissociation constants for peptides derived from flagellar motor protein FliM and phosphatase CheZ were determined for phosphono-CheY and the two mutants. The peptides bind phosphono-CheY almost as strongly as CheY-P; however, they do not bind T87I phosphono-CheY or T87I/Y106W phosphono-CheY, implying that the mutant proteins cannot bind FliM or CheZ tightly in vivo. The structures of T87I phosphono-CheY and T87I/Y106W phosphono-CheY were solved to resolutions of 1.8 and 2.4 {angstrom}, respectively. The increased bulk of I87 forces the side-chain of Y106 or W106, into a more solvent-accessible conformation, which occludes the peptide-binding site.
- Research Organization:
- Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1006978
- Journal Information:
- Arch. Biochem. Biophys., Vol. 479, Issue (2) ; 11, 2008; ISSN 0003-9861
- Country of Publication:
- United States
- Language:
- ENGLISH
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