A structure-specific endonuclease that resolves Holliday junction (HJ) intermediates during genetic recombination. Cleaves 4-way DNA junctions introducing paired nicks in opposing strands, leaving a 5'-terminal phosphate and a 3'-terminal hydroxyl group that are ligated to produce recombinant products. Cleaves both mobile and immobile junctions. Binds 4-way junction DNA, a synthetic Hj, binding is not competed by dsDNA. Endonucleolytic cleavage at a junction such as a reciprocal single-stranded crossover between two homologous DNA duplexes (Holliday junction). Divalent cations, Mg(2+) has higher activity than Mn(2+). Cleavage inhibited by RadB in the absence (but not presence) of ATP. Optimum pH is 8-10. Optimum temperature is 70-75 degrees Celsius, enzyme is fully active after 16 hours at 90 degrees Celsius. Homodimer. Probably interacts with PCNA and RadB. Belongs to the Holliday junction resolvase Hjc family.