Can catalyze the hydrolysis of ATP in the presence of single-stranded DNA, the ATP-dependent uptake of single-stranded DNA by duplex DNA, and the ATP-dependent hybridization of homologous single-stranded DNAs. It interacts with LexA causing its activation and leading to its autocatalytic cleavage. Plays a role in recovery after DNA ADP-ribosylation. Induced by expression of DNA ADP-ribosyl transferase (darT) mutant G49D but not by mutant E170A; G49D has decreased ssDNA ADP-ribosylation activity while E170A has lost the activity (at protein level). Significantly reduced survival of cells expressing DNA ADP-ribosyl transferase (darT) mutant G49D. Belongs to the RecA family.