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. PI-MtuI is an endonuclease. Interacts with UvrD1 and UvrA (PubMed:20455546). Co-immunoprecipitates with DarG in the presence and absence of darT (PubMed:32634279). By DNA damage, and by ADP-ribosylation catalyzed by DarT (at protein level). This protein undergoes a protein self splicing that involves a post-translational excision of the intervening region (intein) followed by peptide ligation. Belongs to the RecA family.