Allosteric priming of E. coli CheY by the flagellar motor protein FliM
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ABSTRACT: We detail simulations and solution measurements to better understand the differences between the native and D13K-Y106W CheY crystal structures. We resolved the complex conformational landscapes by MD simulations with mutual information measures to determine the coupling between protein fragments. Protection experiments with XFMS (X-ray foot-printing with mass spectroscopy), a technique that probed sidechain solvent accessibility in contrast to deuterium exchange of backbone hydrogen atoms, supported the FliMN requirement for D13K-Y106W CheY activation reported by the crystal structures, and the MD allosteric network model. XFMS has a more straight-forward physical rationale than fluorescence quenching for reporting sidechain motions over time-resolved windows and is not limited by the size of the protein assembly. Further analysis of the MD trajectories resolved multiple CheY Y106 rotamer states. Inward orientation was temporally coupled to stabilization of both the CheY fold and the FliMN interface in the CheY·FliMN complex, but not in CheY alone. The coupling increased in D13K-Y106WCheY·FliMN. The formation of a distinct module that orchestrates CheY dynamicsto stabilize new surface topologies for possible second-stage binding to FliN was the signature of the fully activated D13K-Y106W CheY·FliMN state.
INSTRUMENT(S): 6550 iFunnel Q-TOF LC/MS
ORGANISM(S): Escherichia Coli Bl21(de3)
SUBMITTER: Christopher Petzold
LAB HEAD: Christopher J. Petzold
PROVIDER: PXD020434 | Pride | 2020-09-21
REPOSITORIES: Pride
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