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. Antibiotic biosynthesis; prodigiosin biosynthesis. Cells lacking this gene show a white phenotype and produce 4-hydroxy-2,2'-bipyrrole-5-carbaldehyde (HBC), 4- methoxy-2,2'-bipyrrole-5-carbaldehyde (MBC), 4-hydroxy-2,2'-bipyrrole-5-methanol (HBM) and 2-methyl-3-n-amyl-pyrrole (MAP). The mechanism for the condensation reaction is that a phosphoryl group from ATP is transferred via His-840 in the C-terminal phosphoryl transfer domain to the oxygen atom of the aldehyde group of MBC. This exposes the otherwise fairly unreactive aldehyde to modification by the C-5 of MAP. After this initial formation of the C-C bond, the loss of the proton from what had been C-5 of MAP and the elimination of phosphate is possible. Belongs to the PigC family.