Mediates initiation of conjugal transfer possibly by introducing a single-stranded nick at the potential origin of transfer. The gene coding for this protein is interrupted by a group II intron, IntL. Splicing of the intervening intron is necessary for proper protein activity and, therefore, conjugative transfer, as the splicing event brings together the two conserved histidine residues proposed to function as ligands for the metal ion cofactor. Belongs to the mobilization (MOB) protein type 1 family. Intron retention. Intron retention.