Involved in DNA repair and in homologous recombination. Binds and assembles on single-stranded DNA to form a nucleoprotein filament. Hydrolyzes ATP in a ssDNA-dependent manner and promotes DNA strand exchange between homologous DNA molecules (Probable). In addition to its role in homologous recombination plays a critical role in maintenance and/or replication of some plasmids, but not in plasmid transformation. Decreased growth rate, loss of homologous recombination, increased sensitivity to DNA damaging agents such as UV light and ethylmethane sulfonate (EMS). Loss of maintenance and/or replication of pHH1 and pHV2 (but not pHK2) replicon-containing plasmids. Belongs to the eukaryotic RecA-like protein family.