RuvC
RuvC is a DNA repair endonuclease in bacteria, part of the ruvABC operon, which promotes homologous recombination by resolving Holliday junctions. It is a homodimer with subunits of about 18–20 kDa and an RNase H-like fold. RuvC is a metal-dependent nuclease requiring divalent ions (Mg2+ or Mn2+) for catalysis; it cleaves specific DNA at the junction to generate two intact recombinant molecules. In vivo, RuvA and RuvB form a complex at processed Holliday junctions: RuvA binds the junction as a tetramer; RuvB provides the ATP-driven motor activity to promote branch migration, extending the region of exchange until the junction is positioned for cleavage. RuvC then nuclease-incises across the two paired strands of the junction on opposite sides, resolving the junction into two separate DNA duplexes with recombinant termini. The activity of RuvC is sequence-independent and relies on the DNA structure of the Holliday junction rather than its sequence; this ensures resolution regardless of surrounding sequence.
RuvC is widespread in bacteria, encoded by the ruvC gene often adjacent to ruvA and ruvB in