Involved in ATP-dependent DNA-unwinding in a 3' to 5' direction, and ATP-ase activities stimulated by the single-stranded DNA-binding protein ssb1. Essential for viability and normal growth of stationary phase cells and in the absence of either srs2 or rqh1 DNA helicase (PubMed:16135799, PubMed:9228070). Involved in DNA recombination repair of strand breaks and stalled or collapsed replication forks, on the rhp51-dependent pathway: promotes rhp51 filament dissolution from stalled forks, thereby inhibiting homologous recombination and preventing excessive recombination (PubMed:16135800, PubMed:19546232). Ubiquitination and DNA helicase activities are essential for controlling rhp51-dependent recombination in the absence of rad22. Plays a role in the processing of toxic recombination intermediates. Promotes proper chromosome segregation (PubMed:16135799, PubMed:16135800, PubMed:9228070, PubMed:19546232). ATP + H2O = ADP + H(+) + phosphate Protein modification; protein ubiquitination. Part of the E3 ubiquitin ligase Skp1-Cullin-1-F-box (SCF) complex. Interacts with skp1 and ssb1. Becomes localized at discrete nuclear foci together with rhp51, in response to DNA strand breakage. Belongs to the helicase family. UvrD subfamily.