1ehc
STRUCTURE OF SIGNAL TRANSDUCTION PROTEIN CHEYSTRUCTURE OF SIGNAL TRANSDUCTION PROTEIN CHEY
Structural highlights
Function[CHEY_ECOLI] Involved in the transmission of sensory signals from the chemoreceptors to the flagellar motors. In its active (phosphorylated or acetylated) form, CheY exhibits enhanced binding to a switch component, FliM, at the flagellar motor which induces a change from counterclockwise to clockwise flagellar rotation. Overexpression of CheY in association with MotA and MotB improves motility of a ycgR disruption, suggesting there is an interaction (direct or indirect) between the c-di-GMP-binding flagellar brake protein and the flagellar stator.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedAn aspartate to lysine mutation at position 13 of the chemotaxis regulatory protein CheY causes a constitutive tumbly phenotype when expressed at high copy number in vivo even though the mutant protein is not phosphorylatable. These properties suggest that the D13K mutant adopts the active, signaling conformation of CheY independent of phosphorylation, so knowledge of its structure could explain the activation mechanism of CheY. The x-ray crystallographic structure of the CheY D13K mutant has been solved and refined at 2.3 A resolution to an R-factor of 14.3%. The mutant molecule shows no significant differences in backbone conformation when compared with the wild-type, Mg2+-free structure, but there are localized changes within the active site. The side chain of lysine 13 blocks access to the active site, whereas its epsilon-amino group has no bonding interactions with other groups in the region. Also in the active site, the bond between lysine 109 and aspartate 57 is weakened, and the solvent structure is perturbed. Although the D13K mutant has the inactive conformation in the crystalline form, rearrangements in the active site appear to weaken the overall structure of that region, potentially creating a metastable state of the molecule. If a conformational change is required for signaling by CheY D13K, then it most likely proceeds dynamically, in solution. Uncoupled phosphorylation and activation in bacterial chemotaxis. The 2.3 A structure of an aspartate to lysine mutant at position 13 of CheY.,Jiang M, Bourret RB, Simon MI, Volz K J Biol Chem. 1997 May 2;272(18):11850-5. PMID:9115243[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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