title: RecFOR proteins load RecA protein onto gapped DNA to accelerate DNA strand exchange: a universal step of recombinational repair.
abstract: Genetic evidence suggests that the RecF, RecO, and RecR (RecFOR) proteins participate in a common step of DNA recombination and repair, yet the biochemical event requiring collaboration of all three proteins is unknown. Here, we show that the concerted action of the RecFOR complex directs the loading of RecA protein specifically onto gapped DNA that is coated with single-stranded DNA binding (SSB) protein, thereby accelerating DNA strand exchange. The RecFOR complex recognizes the junction between the ssDNA and dsDNA regions and requires a base-paired 5' terminus at the junction. Thus, the RecFOR complex is a structure-specific mediator that targets recombinational repair to ssDNA-dsDNA junctions. This reaction reconstitutes the initial steps of recombinational gapped DNA repair and uncovers an event also common to the repair of ssDNA-tailed intermediates of dsDNA-break repair. We propose that the behavior of the RecFOR proteins is mimicked by functional counterparts that exist in all organisms.
authors.affiliation: Section of Microbiology, Center for Genetics and Development, University of California, Davis, 95616, USA.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Morimatsu
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Kowalczykowski
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D004247:DNA / Q000235:genetics / Q000378:metabolism*; D004249:DNA Damage / Q000235:genetics; D004260:DNA Repair / Q000235:genetics*; D004277:DNA, Single-Stranded / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D005057:Eukaryotic Cells / Q000378:metabolism; D015321:Gene Rearrangement / Q000235:genetics*; D009698:Nucleoproteins / Q000096:biosynthesis / Q000235:genetics; D011387:Prokaryotic Cells / Q000378:metabolism; D011938:Rec A Recombinases / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004277:DNA, Single-Stranded; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D009698:Nucleoproteins; C081006:RecO protein, E coli; C489318:RecR protein, E coli; C489340:recF protein, E coli; C065831:RecR protein, Bacteria; D004247:DNA; C066218:recF protein, Bacteria; D011938:Rec A Recombinases