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 (By similarity). It interacts with LexA causing its activation and leading to its autocatalytic cleavage (By similarity). Required for DNA transformation; protects transforming DNA from degradation, possibly in combination with DprA (PubMed:14617176, PubMed:17803906). Present at 15,000-30,000 monomers per competent cell (PubMed:14617176). Interacts with DprA; probably forms mixed DprA-RecA-ssDNA filaments (PubMed:17803906). By competence and DNA damage (PubMed:7798154). Loss of DNA transformation; incoming DNA is very rapidly degraded (PubMed:14617176). Belongs to the RecA family.