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 (By similarity). Has a role that partially overlaps that of Hef endonuclease; double deletions cannot be constructed. In the presence of site-directed mutations that (probably) abolish Hef helicase or nuclease activity, a hjc deletion cannot be constructed. Endonucleolytic cleavage at a junction such as a reciprocal single-stranded crossover between two homologous DNA duplexes (Holliday junction). Binds 1 Mg(2+) ion per subunit. Homodimer. No alteration in sensitivity to UV light, slow growth on mitomycin C. No effect on homologous recombination; double hef/hjc deletion mutants cannot be constructed (synthetic lethality), suggesting the enzymes play overlapping roles. Belongs to the Holliday junction resolvase Hjc family.