DNA-dependent ATPase and 3'-5' DNA helicase that may be involved in repair of stalled replication forks. ATP + H2O = ADP + H(+) + phosphate Monomer. The N-terminal region (1-400) has DNA-dependent ATPase activity but no helicase activity. Belongs to the helicase family. Hel308 subfamily. This open reading frame is annotated as an authentic frameshift in the genome.