1. Structural Biology and Molecular Biophysics
  2. Microbiology and Infectious Disease
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Structural basis for the inhibition of RecBCD by Gam and its synergistic antibacterial effect with quinolones

  1. Martin Wilkinson
  2. Lucy Troman
  3. Wan AK Wan Nur Ismah
  4. Yuriy Chaban
  5. Matthew B Avison
  6. Mark Simon Dillingham  Is a corresponding author
  7. Dale B Wigley  Is a corresponding author
  1. Imperial College London, United Kingdom
  2. University of Bristol, United Kingdom
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Cite this article as: eLife 2016;5:e22963 doi: 10.7554/eLife.22963

Abstract

In previous work we used high-resolution cryo-electron microscopy to solve the structure of the Escherichia coli RecBCD complex, which acts in both the repair of double-stranded DNA breaks and the degradation of bacteriophage DNA (Wilkinson et al, 2016). To counteract the latter activity, bacteriophage λ encodes a small protein inhibitor called Gam that binds to RecBCD and inactivates the complex. Here, we show that Gam inhibits RecBCD by competing at the DNA-binding site. The interaction surface is extensive and involves molecular mimicry of the DNA substrate. We also show that expression of Gam in E. coli or Klebsiella pneumoniae increases sensitivity to fluoroquinolones; antibacterials that kill cells by inhibiting topoisomerases and inducing double-stranded DNA breaks. Furthermore, fluoroquinolone-resistance in K. pneumoniae clinical isolates is reversed by expression of Gam. Together, our data explain the synthetic lethality observed between topoisomerase-induced DNA breaks and the RecBCD gene products, suggesting a new co-antibacterial strategy.

Article and author information

Author details

  1. Martin Wilkinson

    Section of Structural Biology, Imperial College London, London, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  2. Lucy Troman

    School of Biochemistry, University of Bristol, Bristol, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  3. Wan AK Wan Nur Ismah

    School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  4. Yuriy Chaban

    Section of Structural Biology, Imperial College London, London, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  5. Matthew B Avison

    School of Cellular and Molecular Medicine, University of Bristol, Bristol, United Kingdom
    Competing interests
    The authors declare that no competing interests exist.
  6. Mark Simon Dillingham

    School of Biochemistry, University of Bristol, Bristol, United Kingdom
    For correspondence
    mark.dillingham@bristol.ac.uk
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-4612-7141
  7. Dale B Wigley

    Section of Structural Biology, Imperial College London, London, United Kingdom
    For correspondence
    d.wigley@imperial.ac.uk
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-0786-6726

Funding

Wellcome (095519/B/11/Z)

  • Dale B Wigley

Medical Research Council (MR/N009258/1)

  • Dale B Wigley

Cancer Research UK (A12799)

  • Dale B Wigley

Wellcome (100401/Z/12/Z)

  • Mark Simon Dillingham

Engineering and Physical Sciences Research Council (EP/M027546/1)

  • Matthew B Avison

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. David Sherratt, University of Oxford, United Kingdom

Publication history

  1. Received: November 11, 2016
  2. Accepted: December 22, 2016
  3. Accepted Manuscript published: December 23, 2016 (version 1)
  4. Version of Record published: January 6, 2017 (version 2)

Copyright

© 2016, Wilkinson 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. Further reading

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