Mediates initition of conjugal transfer of plasmid pRS01 possibly by introducing a single-stranded nick at the potential origin of transfer, to initiate single strand transfer from donor to recipient. The gene coding for this protein is interrupted by a group II intron, Ll.LtrB. Splicing of the intervening intron is necessary for proper protein activity and, therefore, conjugative transfer of pRS01, 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.