Involved in the biosynthesis of 4-methoxy-2,2'-bipyrrole-5-carbaldehyde (MBC), one of the terminal products involved in the biosynthesis of the red antibiotic prodigiosin (Pig) (PubMed:15853884, PubMed:17002325). Catalyzes the conversion of L-proline to L-prolyl-AMP and the transfer of the L-prolyl group to acyl carrier protein PigG (PubMed:17002325). ATP + holo-[peptidyl-carrier protein] + L-proline = AMP + diphosphate + L-prolyl-[peptidyl-carrier protein] Antibiotic biosynthesis; prodigiosin biosynthesis. Cells lacking this gene show a white phenotype and produce 2-methyl-3-n-amyl-pyrrole (MAP). Belongs to the ATP-dependent AMP-binding enzyme family.