title: A key presynaptic role in transformation for a widespread bacterial protein: DprA conveys incoming ssDNA to RecA.
abstract: Natural transformation is a mechanism for genetic exchange in many bacterial genera. It proceeds through the uptake of exogenous DNA and subsequent homology-dependent integration into the genome. In Streptococcus pneumoniae, this integration requires the ubiquitous recombinase, RecA, and DprA, a protein of unknown function widely conserved in bacteria. To unravel the role of DprA, we have studied the properties of the purified S. pneumoniae protein and its Bacillus subtilis ortholog (Smf). We report that DprA and Smf bind cooperatively to single-stranded DNA (ssDNA) and that these proteins both self-interact and interact with RecA. We demonstrate that DprA-RecA-ssDNA filaments are produced and that these filaments catalyze the homology-dependent formation of joint molecules. Finally, we show that while the Escherichia coli ssDNA-binding protein SSB limits access of RecA to ssDNA, DprA lowers this barrier. We propose that DprA is a new member of the recombination-mediator protein family, dedicated to natural bacterial transformation.
authors.affiliation: Laboratoire de Microbiologie et Génétique Moléculaires, UMR 5100 CNRS-Université Paul Sabatier, 118 route de Narbonne, 31062 Toulouse Cedex 09, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Mortier-Barrière
authors.forename: Marion
authors.initials: M
authors.lastname: Velten
authors.forename: Pauline
authors.initials: P
authors.lastname: Dupaigne
authors.forename: Nicolas
authors.initials: N
authors.lastname: Mirouze
authors.forename: Olivier
authors.initials: O
authors.lastname: Piétrement
authors.forename: Stephen
authors.initials: S
authors.lastname: McGovern
authors.forename: Gwennaele
authors.initials: G
authors.lastname: Fichant
authors.forename: Bernard
authors.initials: B
authors.lastname: Martin
authors.forename: Philippe
authors.initials: P
authors.lastname: Noirot
authors.forename: Eric
authors.initials: E
authors.lastname: Le Cam
authors.forename: Patrice
authors.initials: P
authors.lastname: Polard
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Claverys
mesh_terms: D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000201:enzymology / Q000378:metabolism; D004269:DNA, Bacterial / Q000378:metabolism*; D004270:DNA, Circular / Q000378:metabolism; D004277:DNA, Single-Stranded / Q000378:metabolism*; D004278:DNA, Superhelical / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D019143:Evolution, Molecular; D005090:Exodeoxyribonucleases / Q000378:metabolism; D042822:Genomic Instability; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D011938:Rec A Recombinases / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D011995:Recombination, Genetic; D013296:Streptococcus pneumoniae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D014169:Transformation, Bacterial