Involved in DNA double-strand break (DSB) repair (PubMed:12052775). Acts probably with HerA to stimulate resection of the 5' strand and produce the long 3' single-strand that is required for RadA loading (By similarity). Exhibits both single-stranded endonuclease activity and 5'-3' exonuclease activity on single-stranded and double-stranded DNA (PubMed:12052775). Belongs to the NurA family.