2b1j
From Proteopedia
Crystal Structure of Unphosphorylated CheY Bound to the N-Terminus of FliM
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] [FLIM_ECOLI] FliM is one of three proteins (FliG, FliN, FliM) that forms the rotor-mounted switch complex (C ring), located at the base of the basal body. This complex interacts with the CheY and CheZ chemotaxis proteins, in addition to contacting components of the motor that determine the direction of flagellar rotation. 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 PubMedPhosphorylation of Escherichia coli CheY increases its affinity for its target, FliM, 20-fold. The interaction between BeF(3)(-)-CheY, a phosphorylated CheY (CheY approximately P) analog, and the FliM sequence that it binds has been described previously in molecular detail. Although the conformation that unphosphorylated CheY adopts in complex with FliM was unknown, some evidence suggested that it is similar to that of CheY approximately P. To resolve the issue, we have solved the crystallographic structure of unphosphorylated, magnesium(II)-bound CheY in complex with a synthetic peptide corresponding to the target region of FliM (the 16 N-terminal residues of FliM [FliM(16)]). While the peptide conformation and binding site are similar to those of the BeF(3)(-)-CheY-FliM(16) complex, the inactive CheY conformation is largely retained in the unphosphorylated Mg(2+)-CheY-FliM(16) complex. Communication between the target binding site and the phosphorylation site, observed previously in biochemical experiments, is enabled by a network of conserved side chain interactions that partially mimic those observed in BeF(3)(-)-activated CheY. This structure makes clear the active role that the beta4-alpha4 loop plays in the Tyr(87)-Tyr(106) coupling mechanism that enables allosteric communication between the phosphorylation site and the target binding surface. Additionally, this structure provides a high-resolution view of an intermediate conformation of a response regulator protein, which had been generally assumed to be two state. Switched or not?: the structure of unphosphorylated CheY bound to the N terminus of FliM.,Dyer CM, Dahlquist FW J Bacteriol. 2006 Nov;188(21):7354-63. PMID:17050923[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
| ||||||||||||||||||||||
