DNA helicase that plays a role in DNA damage repair and genome stability. Exhibits a magnesium- and ATP-dependent DNA-helicase activity that unwinds single- and double-stranded DNA in a 3'-5' direction. Plays a role in restoring regressed replication forks. Required to restart stalled replication forks induced by abortive topoisomerase 1 and 2 lesions. May play a role in the repair of DNA that is damaged by ultraviolet light or other mutagens 