title: An SOS inhibitor that binds to free RecA protein: the PsiB protein.
abstract: The process of bacterial conjugation involves the transfer of a conjugative plasmid as a single strand. The potentially deleterious SOS response, which is normally triggered by the appearance of single-stranded DNA, is suppressed in the recipient cell by a conjugative plasmid system centered on the product of the psiB gene. The F plasmid PsiB protein inhibits all activities of the RecA protein, including DNA binding, DNA strand exchange, and LexA protein cleavage. The proteins known to negatively regulate recombinases, such as RecA or Rad51, generally work at the level of dismantling the nucleoprotein filament. However, PsiB binds to RecA protein that is free in solution. The RecA-PsiB complex impedes formation of RecA nucleoprotein filaments on DNA.
authors.affiliation: Program in Cellular and Molecular Biology, University of Wisconsin, Madison, Madison, WI 53706, USA.
authors.forename: Vessela
authors.initials: V
authors.lastname: Petrova
authors.forename: Sindhu
authors.initials: S
authors.lastname: Chitteni-Pattu
authors.forename: Julia C
authors.initials: JC
authors.lastname: Drees
authors.forename: Ross B
authors.initials: RB
authors.lastname: Inman
authors.forename: Michael M
authors.initials: MM
authors.lastname: Cox
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003227:Conjugation, Genetic / Q000502:physiology; D003434:Crossing Over, Genetic / Q000235:genetics; D004247:DNA / Q000235:genetics / Q000378:metabolism; D004270:DNA, Circular / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D004277:DNA, Single-Stranded / Q000378:metabolism / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000378:metabolism; D004926:Escherichia coli / Q000502:physiology; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D005454:Fluorescence Polarization; D008957:Models, Genetic; D011071:Poly T / Q000378:metabolism; D011485:Protein Binding / Q000502:physiology; D011938:Rec A Recombinases / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013014:SOS Response, Genetics / Q000502:physiology*; D012697:Serine Endopeptidases / Q000378:metabolism; D000099160:LexA Repressor Protein
chemical_list: D000255:Adenosine Triphosphate; D001426:Bacterial Proteins; D004247:DNA; D004270:DNA, Circular; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D011071:Poly T; D011938:Rec A Recombinases; D011994:Recombinant Proteins; D012697:Serine Endopeptidases; D000099160:LexA Repressor Protein; C422844:DinI protein, E coli; C058074:PsiB protein, Bacteria; C476430:SSB protein, E coli