Structural basis for the inhibition of RecBCD by Gam and its synergistic antibacterial effect with quinolones
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Published version
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Author(s)
Type
Journal Article
Abstract
Our previous paper (Wilkinson et al, 2016) 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. 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.
Date Issued
2016-12-23
Date Acceptance
2016-12-23
Citation
eLife, 2016, 5
ISSN
2050-084X
Publisher
eLife Sciences Publications
Journal / Book Title
eLife
Volume
5
Copyright Statement
© Copyright Wilkinson et al. This
article is distributed under the
terms of the Creative Commons
Attribution License, which
permits unrestricted use and
redistribution provided that the
original author and source are
credited.
article is distributed under the
terms of the Creative Commons
Attribution License, which
permits unrestricted use and
redistribution provided that the
original author and source are
credited.
Sponsor
Wellcome Trust
Cancer Research UK
Medical Research Council (MRC)
Wellcome Trust
Cancer Research UK
Grant Number
095519/B/11/Z
C6913/A12799
MR/N009258/1
202926/Z/16/Z
C6913/A21608
Publication Status
Published
Article Number
e22963