Involved in DNA double-strand break (DSB) repair (PubMed:14990749). Acts probably with NurA to stimulate resection of the 5' strand and produce the long 3' single-strand that is required for RadA loading (By similarity). Exhibits DNA-dependent ATPase activity and DNA helicase activity (PubMed:14990749). Loads on either a 3' or a 5' DNA tail for subsequent DNA unwinding (PubMed:14990749). ATP + H2O = ADP + H(+) + phosphate ATPase activity is slightly stimulated by either circular single- or double-stranded DNA with a weak preference for double-stranded DNA. Interacts with Rad50 and Mre11. Belongs to the HerA family.