CryoEM and computer simulations reveal a novel kinase conformational switch in bacterial chemotaxis signaling

  1. C Keith Cassidy
  2. Benjamin A Himes
  3. Frances J Alvarez
  4. Jun Ma
  5. Gongpu Zhao
  6. Juan R Perilla
  7. Klaus Schulten
  8. Peijun Zhang  Is a corresponding author
  1. University of Illinois at Urbana-Champaign, United States
  2. University of Pittsburgh School of Medicine, United States

Abstract

Chemotactic responses in bacteria require large, highly ordered arrays of sensory proteins to mediate the signal transduction that ultimately controls cell motility. A mechanistic understanding of the molecular events underlying signaling, however, has been hampered by the lack of a high-resolution structural description of the extended array. Here, we report a novel reconstitution of the array, involving the receptor signaling domain, histidine kinase CheA, and adaptor protein CheW, as well as a density map of the core-signaling unit at 11.3 Å resolution, obtained by cryo-electron tomography and sub-tomogram averaging. Extracting key structural constraints from our density map, we computationally construct and refine an atomic model of the core array structure, exposing novel interfaces between the component proteins. Using all-atom molecular dynamics simulations, we further reveal a distinctive conformational change in CheA. Mutagenesis and chemical cross-linking experiments confirm the importance of the conformational dynamics of CheA for chemotactic function.

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Author details

  1. C Keith Cassidy

    Department of Physics and Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Benjamin A Himes

    Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Frances J Alvarez

    Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Jun Ma

    Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Gongpu Zhao

    Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Juan R Perilla

    Department of Physics and Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, United States
    Competing interests
    The authors declare that no competing interests exist.
  7. Klaus Schulten

    Department of Physics and Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, United States
    Competing interests
    The authors declare that no competing interests exist.
  8. Peijun Zhang

    Department of Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, United States
    For correspondence
    pez7@pitt.edu
    Competing interests
    The authors declare that no competing interests exist.

Reviewing Editor

  1. Axel T Brunger, Stanford University, United States

Version history

  1. Received: April 29, 2015
  2. Accepted: November 18, 2015
  3. Accepted Manuscript published: November 19, 2015 (version 1)
  4. Version of Record published: December 31, 2015 (version 2)

Copyright

© 2015, Cassidy et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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  1. C Keith Cassidy
  2. Benjamin A Himes
  3. Frances J Alvarez
  4. Jun Ma
  5. Gongpu Zhao
  6. Juan R Perilla
  7. Klaus Schulten
  8. Peijun Zhang
(2015)
CryoEM and computer simulations reveal a novel kinase conformational switch in bacterial chemotaxis signaling
eLife 4:e08419.
https://doi.org/10.7554/eLife.08419

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https://doi.org/10.7554/eLife.08419

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