ATP-dependent branch migration of Holliday junctions promoted by the RuvA and RuvB proteins of E. coli.
The RuvA and RuvB proteins of E. coli, which are induced as part of the cellular response to DNA damage, act together to promote the branch migration of Holliday junctions. Addition of purified RuvA and RuvB to a RecA-mediated recombination reaction stimulates the rate of strand exchange and the formation of hetero-duplex DNA. Stimulation does not occur via interaction with RecA; instead, RuvA and RuvB act directly upon recombination intermediates (Holliday junctions) made by RecA. We show that RuvAB-mediated branch migration requires ATP and can bypass UV-induced DNA lesions. At high RuvB concentrations, the requirement for RuvA is overcome, indicating that the RuvB ATPase provides the motor force for branch migration. RuvA protein provides specificity by binding to the Holliday junction, thereby reducing the requirement for RuvB by 50-fold. The newly discovered biochemical properties of RuvA, RuvB, and RuvC are incorporated into a model for the postreplicational repair of DNA following UV irradiation.
Tsaneva
I R
IR
Imperial Cancer Research Fund, Clare Hall Laboratories, South Mimms, Herts, England.
Müller
B
B
West
S C
SC
D000255:Adenosine Triphosphate; D001426:Bacterial Proteins / Q000494:pharmacology*; D004247:DNA / Q000187:drug effects*; D004249:DNA Damage; D004265:DNA Helicases; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000494:pharmacology*; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D008958:Models, Molecular; D011995:Recombination, Genetic / Q000187:drug effects
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C061260:RuvB protein, Bacteria; D000255:Adenosine Triphosphate; D004247:DNA; C071059:Holliday junction DNA helicase, E coli; D004265:DNA Helicases