Structures of RecBCD in complex with phage-encoded inhibitor proteins reveal distinctive strategies for evasion of a bacterial immunity hub
- Imperial College London, United Kingdom
- University of Bristol, United Kingdom
Abstract
Following infection of bacterial cells, bacteriophage modulate double-stranded DNA break repair pathways to protect themselves from host immunity systems and prioritise their own recombinases. Here we present biochemical and structural analysis of two phage proteins, gp5.9 and Abc2, which target the DNA break resection complex RecBCD. These exemplify two contrasting mechanisms for control of DNA break repair in which the RecBCD complex is either inhibited or co-opted for the benefit of the invading phage. Gp5.9 completely inhibits RecBCD by preventing it from binding to DNA. The RecBCD-gp5.9 structure shows that gp5.9 acts by substrate mimicry, binding predominantly to the RecB arm domain and competing sterically for the DNA binding site. Gp5.9 adopts a parallel coiled-coil architecture that is unprecedented for a natural DNA mimic protein. In contrast, binding of Abc2 does not substantially affect the biochemical activities of isolated RecBCD. The RecBCD-Abc2 structure shows that Abc2 binds to the Chi-recognition domains of the RecC subunit in a position that might enable it to mediate the loading of phage recombinases onto its single-stranded DNA products.
Data availability
Source data files have been provided for gel-based analyses (Figure 1 - Source data 1).All new cryoEM data/models generated in this work have been deposited at the EMDB and PDB (see Table 1 for accession codes).Validation reports have been provided for structural models with submission.
Article and author information
Author details
Oliver J Wilkinson
Mark Simon Dillingham
Funding
Wellcome Trust (100401/Z/12/Z)
- Mark Simon Dillingham
Biotechnology and Biological Sciences Research Council (BB/S007261/1)
- Mark Simon Dillingham
Cancer Research UK (C6913/A2160)
- Dale B Wigley
Wellcome Trust (209327/Z/17/Z)
- Dale B Wigley
Medical Research Council (MR/N009258/1)
- Dale B Wigley
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2022, 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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