Involved in the biosynthesis of 2-methyl-3-n-amyl-pyrrole (MAP), one of the terminal products involved in the biosynthesis of the red antibiotic prodigiosin (Pig). Catalyzes the transfer of 2-methyl-3-n-amyl-pyrrole (MAP) to 4-methoxy-2,2'-bipyrrole-5-carbaldehyde (MBC) to yield prodigiosin. It is able to use substrates with a variety of monocyclic rings in place of the pyrrolic ring A of its natural substrate. Antibiotic biosynthesis; prodigiosin biosynthesis. Belongs to the PigC family.