Component of the BTR double Holliday Junction dissolution complex, which is involved in homologous recombination during meiotic double strand break in the germline (Probable). Stabilizes and positively regulates the localization of the BTR double Holliday Junction dissolution complex component rmh-1 at nuclear foci during meiotic recombination (PubMed:27011106). Participates in DNA replication and repair (By similarity). Exhibits a magnesium-dependent ATP-dependent DNA-helicase activity that unwinds single- and double-stranded DNA in a 3'-5' direction (By similarity). Negatively regulates sister chromatid exchange (SCE) (PubMed:27010650). ATP-dependent DNA helicase that unwinds single- and double-stranded DNA in a 3'-5' direction. Participates in DNA replication and repair. Negatively regulates sister chromatid exchange (SCE) (PubMed:27010650). Stimulates DNA 4-way junction branch migration and DNA Holliday junction dissolution. Binds single-stranded DNA (ssDNA), forked duplex DNA and DNA Holliday junction. ATP + H2O = ADP + H(+) + phosphate Binds 1 zinc ion per subunit. Monomer (By similarity). Homodimer (via N-terminus) (By similarity). Homotetramer (via N-terminus); dimer of dimers (By similarity). Homohexamer (via N-terminus) (By similarity). Self-association negatively regulates DNA unwinding amplitude and rate (By similarity). Oligomer forms dissociate into monomer in presence of ATP (By similarity). Component of the BTR double Holliday Junction dissolution complex composed of at least him-6, top-3, rmh-1 and rmif-2, which is involved in double strand break repair in the germline (Probable). May interact with rmh-1; the interaction is required for mutual stability and localization at nuclear foci (PubMed:27011106). Forms a complex composed of cdc-48.1, him-6 and crp-1; within the complex, interacts with cdc-48.1 (PubMed:18458060). Localizes on chromosomes during pachytene in meiotic prophase I in oocytes. Co-localizes with rmh-1 at mid-pachytene and late-pachytene in meiotic prophase I (PubMed:27011106). Localization at nuclear foci is dependent on rmh-1 during meiotic recombination (PubMed:27011106). The N-terminal region mediates dimerization and homooligomerization. Both the helicase ATP-binding domain and the helicase C-terminal domain form intramolecular interactions with the HRDC domain in a ATP-dependent manner. The HRDC domain is required for single-stranded DNA (ssDNA) and DNA Holliday junction binding. Reduced viability, increased rad-51 foci in the germline and an increase of meiotic crossover formation in the central region of chromosomes (PubMed:27010650). Reduced number of rmh-1 foci in the pachytene region (PubMed:27011106). In an smc-5 mutant background, defects in diakinetic chiasmata formation, compromised chromosome segregation and aberrant distribution of the condensin II subunit hcp-6 in meiosis (PubMed:27010650). Belongs to the helicase family. RecQ subfamily.