Plays a critical role in recombination and DNA repair. Helps process Holliday junction intermediates to mature products by catalyzing branch migration. Has a DNA unwinding activity characteristic of a DNA helicase with 3'- to 5'- polarity. Unwinds branched duplex DNA (Y-DNA). Has a role in constitutive stable DNA replication (cSDR) and R-loop formation. Is genetically synergistic to RadA and RuvABC (PubMed:12446634, PubMed:25484163). ATP + H2O = ADP + H(+) + phosphate Very slight sensitivity to ciprofloxacin (CFX), UV and azidothymidine (AZT) in single deletion mutants, but a radA-recG deletion is extremely sensitive to CFX and AZT, less so to UV (PubMed:12446634, PubMed:25484163). The SOS response is induced in this double mutant, indicating spontaneous DNA damage. AZT sensitivity is suppressed by further recA or recF deletions, suggesting AZT-induced DNA gaps are processed into lethal intermediates in a RecA-dependent fashion mediated by RecF (PubMed:25484163). Belongs to the helicase family. RecG subfamily.