RuvC Protein, E.coli (His-SUMO)

The RuvC protein is an essential component of the RuvA-RuvB-RuvC complex, which plays a crucial role in processing Holliday junctions during genetic recombination and DNA repair. As an endonuclease, RuvC resolves Holliday junction (HJ) intermediates by making single-stranded nicks across the junction at symmetrical positions within the homologous arms. This cleavage results in the generation of a 5'-phosphate and a 3'-hydroxyl group and is dependent on the presence of a central core of homology in the junction. The consensus cleavage sequence for RuvC is 5'-(A/T)TT(C>G/A)-3', with cleavage occurring on the 3'-side of the TT dinucleotide at the point of strand exchange. Notably, the cleavage reactions can be uncoupled, requiring the presence of two consensus cleavage sequences. RuvC binds to cruciform DNA in a sequence non-specific manner. In conjunction with RuvA and RuvB, RuvC forms a complex that enhances the rate of strand exchange (branch migration), dissociates the RecA filament, and facilitates cleavage in both orientations at the cruciform junction. The HJ-RuvA-RuvB-RuvC complexes not only resolve Holliday junctions but also undergo branch migration, demonstrating a coupled branch migration/HJ resolution reaction. This comprehensive enzymatic activity of RuvC underscores its pivotal role in the intricate machinery of DNA repair and recombination.