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Nucleic Acids Res. 2014 Jun;42(11):7395-408. doi: 10.1093/nar/gku349. Epub 2014 Apr 29.

Molecular determinants of the DprA-RecA interaction for nucleation on ssDNA.

Author information

1
Université Paris-Sud, Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, UMR 8619, F-91405 Orsay, France.
2
CEA, iBiTecS, F-91191 Gif sur Yvette, France Université Paris-Sud & CNRS, UMR 8221, F-91191 Gif sur Yvette, France.
3
Université Paris-Sud, Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, UMR 8619, F-91405 Orsay, France UFR sciences de la vie, Université Pierre et Marie Curie UPMC, Sorbonne Universités, F-75005 Paris, France.
4
CEA, iBiTecS, F-91191 Gif sur Yvette, France Université Paris-Sud & CNRS, UMR 8221, F-91191 Gif sur Yvette, France raphael.guerois@cea.fr.
5
Université Paris-Sud, Institut de Biochimie et de Biophysique Moléculaire et Cellulaire, UMR 8619, F-91405 Orsay, France sophie.quevillon-cheruel@u-psud.fr.

Abstract

Natural transformation is a major mechanism of horizontal gene transfer in bacteria that depends on DNA recombination. RecA is central to the homologous recombination pathway, catalyzing DNA strand invasion and homology search. DprA was shown to be a key binding partner of RecA acting as a specific mediator for its loading on the incoming exogenous ssDNA. Although the 3D structures of both RecA and DprA have been solved, the mechanisms underlying their cross-talk remained elusive. By combining molecular docking simulations and experimental validation, we identified a region on RecA, buried at its self-assembly interface and involving three basic residues that contact an acidic triad of DprA previously shown to be crucial for the interaction. At the core of these patches, (DprA)M238 and (RecA)F230 are involved in the interaction. The other DprA binding regions of RecA could involve the N-terminal α-helix and a DNA-binding region. Our data favor a model of DprA acting as a cap of the RecA filament, involving a DprA-RecA interplay at two levels: their own oligomeric states and their respective interaction with DNA. Our model forms the basis for a mechanistic explanation of how DprA can act as a mediator for the loading of RecA on ssDNA.

PMID:
24782530
PMCID:
PMC4066776
DOI:
10.1093/nar/gku349
[Indexed for MEDLINE]
Free PMC Article

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