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. Inhibits the helicase activity of Hel308 (Hjm). 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. Cleavage stimulated by PCNA123 and PCNA323 (PubMed:18782564) and by RadC2 (PubMed:22437993). Homodimer; forms a 2:1 complex with Hel308 (Hjm). May form a complex with Holliday junction DNA, Hjc and Hjm. Belongs to the Holliday junction resolvase Hjc family.