CRYSTAL-STRUCTURE OF DNA RECOMBINATION PROTEIN RUVA AND A MODEL FOR ITS BINDING TO THE HOLLIDAY JUNCTION

The Escherichia coli DNA binding protein RuvA acts in concert with the helicase RuvB to drive branch migration of Holliday intermediates dur ing recombination and DNA repair. The atomic structure of RuvA was det ermined at a resolution of 1.9 angstroms. Four monomers of RuvA are re lated by fourfold symmetry in a manner reminiscent of a four-petaled f lower. The four DNA duplex arms of a Holliday junction can be modeled in a square planar configuration and docked into grooves on the concav e surface of the protein around a central pin that may facilitate stra nd separation during the migration reaction. The model presented revea ls how a RuvAB-junction complex may also accommodate the resolvase Ruv C.