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). Carrier of the L-prolyl group transferred from L-prolyl-AMP by PigI. Antibiotic biosynthesis; prodigiosin biosynthesis. Cells lacking this gene show a white phenotype and produce 2-methyl-3-n-amyl-pyrrole (MAP).