Bacillus subtilis RecA with DprA–SsbA antagonizes RecX function during natural transformation. Issue 15 (7th July 2017)

• Record Type: Journal Article
• Authors: Le, Shimin; Serrano, Ester; Kawamura, Ryo; Carrasco, Begoña; Yan, Jie; Alonso, Juan C.
• Is Part Of: Nucleic acids research. Volume 45:Issue 15(2017)
• Page Start: 8873
• Page End: 8885
• Publication Date: 2017-07-07
• Subjects: Nucleic acids -- Periodicals; Molecular biology -- Periodicals; 572.805
• DOI: 10.1093/nar/gkx583
• Languages: English
• ISSNs: 0305-1048

Abstract

Abstract: Bacillus subtilis DprA and RecX proteins, which interact with RecA, are crucial for efficient chromosomal and plasmid transformation. We showed that RecA, in the rATP·Mg 2+ bound form (RecA·ATP), could not compete with RecX, SsbA or SsbB for assembly onto single-stranded (ss)DNA, but RecA·dATP partially displaced these proteins from ssDNA. RecX promoted reversible depolymerization of preformed RecA·ATP filaments. The two-component DprA–SsbA mediator reversed the RecX negative effect on RecA filament extension, but not DprA or DprA and SsbB. In the presence of DprA–SsbA, RecX added prior to RecA·ATP inhibited DNA strand exchange, but this inhibition was reversed when RecX was added after RecA. We propose that RecA nucleation is more sensitive to RecX action than is RecA filament growth. DprA–SsbA facilitates formation of an active RecA filament that directly antagonizes the inhibitory effects of RecX. RecX and DprA enable chromosomal transformation by altering RecA filament dynamics. DprA–SsbA and RecX proteins constitute a new regulatory network of RecA function. DprA–SsbA contributes to the formation of an active RecA filament and directly antagonizes the inhibitory effects of RecX during natural transformation.