Multifunctional enzyme that has magnesium and ATP-dependent 3′-5′ DNA-helicase activity on partially duplex substrates (PubMed:9224595, PubMed:9288107, PubMed:9611231). Also has 3′->5′ exonuclease activity towards double-stranded DNA with a 5′-overhang (PubMed:11863428). Has no nuclease activity towards single-stranded DNA or blunt-ended double-stranded DNA (PubMed:11863428). Helicase activity is most efficient with (d)ATP, but (d)CTP will substitute with reduced efficiency; strand displacement is enhanced by single-strand binding-protein (heterotrimeric replication protein A complex, RPA1, RPA2, RPA3) (PubMed:9611231). Binds preferentially to DNA substrates containing alternate secondary structures, such as replication forks and Holliday junctions. May play an important role in the dissociation of joint DNA molecules that can arise as products of homologous recombination, at stalled replication forks or during DNA repair. Alleviates stalling of DNA polymerases at the site of DNA lesions. Important for genomic integrity. Plays a role in the formation of DNA replication focal centers; stably associates with foci elements generating binding sites for RP-A (By similarity). Plays a role in double-strand break repair after gamma-irradiation (PubMed:9224595, PubMed:9288107, PubMed:9611231). Depletion leads to chromosomal breaks and genome instability (PubMed:33199508).
