title: Functional interactions between the holliday junction resolvase and the branch migration motor of Escherichia coli.
abstract: Homologous recombination generates genetic diversity and provides an important cellular pathway for the repair of double-stranded DNA breaks. Two key steps in this process are the branch migration of Holliday junctions followed by their resolution into mature recombination products. In E.coli, branch migration is catalysed by the RuvB protein, a hexameric DNA helicase that is loaded onto the junction by RuvA, whereas resolution is promoted by the RuvC endonuclease. Here we provide direct evidence for functional interactions between RuvB and RuvC that link these biochemically distinct processes. Using synthetic Holliday junctions, RuvB was found to stabilize the binding of RuvC to a junction and to stimulate its resolvase activity. Conversely, RuvC facilitated interactions between RuvB and the junction such that RuvBC complexes catalysed branch migration. The observed synergy between RuvB and RuvC provides new insight into the structure and function of a RuvABC complex that is capable of facilitating branch migration and resolution of Holliday junctions via a concerted enzymatic mechanism.
authors.affiliation: Imperial Cancer Research Fund, Clare Hall Laboratories, South Mimms, Hertfordshire EN6 3LD, UK.
authors.forename: A J
authors.initials: AJ
authors.lastname: van Gool
authors.forename: R
authors.initials: R
authors.lastname: Shah
authors.forename: C
authors.initials: C
authors.lastname: Mézard
authors.forename: S C
authors.initials: SC
authors.lastname: West
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D004247:DNA / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D004265:DNA Helicases; D004268:DNA-Binding Proteins / Q000502:physiology; D004706:Endodeoxyribonucleases / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D009690:Nucleic Acid Conformation; D011995:Recombination, Genetic / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C061260:RuvB protein, Bacteria; C069806:ruvC protein, E coli; D004247:DNA; D004706:Endodeoxyribonucleases; C071059:Holliday junction DNA helicase, E coli; D004265:DNA Helicases