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Functional interactions between the Holliday junction resolvase and the branch migration motor of Escherichia coli
Author(s) -
van Gool Alain J.,
Shah Rajvee,
Mézard Christine,
West Stephen C.
Publication year - 1998
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/17.6.1838
Subject(s) - holliday junction , branch migration , tn3 transposon , biology , homologous recombination , dna , endonuclease , microbiology and biotechnology , helicase , dna repair , genetic recombination , genetics , biophysics , recombination , mutant , gene , transposable element , rna
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.