Crystal Structures of Beryllium Fluoride-free and Beryllium Fluoride-bound CheY in Complex with the Conserved C-terminal Peptide of CheZ Reveal Dual Binding Modes Specific to CheY Conformation

Jayita Guhaniyogi, Victoria L. Robinson, Ann M. Stock

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

Chemotaxis, the environment-specific swimming behavior of a bacterial cell is controlled by flagellar rotation. The steady-state level of the phosphorylated or activated form of the response regulator CheY dictates the direction of flagellar rotation. CheY phosphorylation is regulated by a fine equilibrium of three phosphotransfer activities: phosphorylation by the kinase CheA, its auto-dephosphorylation and dephosphorylation by its phosphatase CheZ. Efficient dephosphorylation of CheY by CheZ requires two spatially distinct protein-protein contacts: tethering of the two proteins to each other and formation of an active site for dephosphorylation. The former involves interaction of phosphorylated CheY with the small highly conserved C-terminal helix of CheZ (CheZC), an indispensable structural component of the functional CheZ protein. To understand how the CheZC helix, representing less than 10% of the full-length protein, ascertains molecular specificity of binding to CheY, we have determined crystal structures of CheY in complex with a synthetic peptide corresponding to 15 C-terminal residues of CheZ (CheZ200-214) at resolutions ranging from 2.0 Å to 2.3 Å. These structures provide a detailed view of the CheZC peptide interaction both in the presence and absence of the phosphoryl analog, BeF3-. Our studies reveal that two different modes of binding the CheZ200-214 peptide are dictated by the conformational state of CheY in the complex. Our structures suggest that the CheZC helix binds to a "meta-active" conformation of inactive CheY and it does so in an orientation that is distinct from the one in which it binds activated CheY. Our dual binding mode hypothesis provides implications for reverse information flow in CheY and extends previous observations on inherent resilience in CheY-like signaling domains.

Original languageEnglish (US)
Pages (from-to)624-645
Number of pages22
JournalJournal of molecular biology
Volume359
Issue number3
DOIs
StatePublished - Jun 9 2006

All Science Journal Classification (ASJC) codes

  • Structural Biology
  • Molecular Biology

Keywords

  • CheY
  • CheZ peptide
  • beryllium fluoride
  • crystal structure
  • dual binding mode

Fingerprint Dive into the research topics of 'Crystal Structures of Beryllium Fluoride-free and Beryllium Fluoride-bound CheY in Complex with the Conserved C-terminal Peptide of CheZ Reveal Dual Binding Modes Specific to CheY Conformation'. Together they form a unique fingerprint.

Cite this