Involved in the biosynthesis of undecylprodigiosin (PubMed:11514230, PubMed:11880032). Catalyzes the conversion of L-proline to L-prolyl-AMP and the transfer of the L-prolyl group to acyl carrier protein RedO (PubMed:11880032). ATP + holo-[peptidyl-carrier protein] + L-proline = AMP + diphosphate + L-prolyl-[peptidyl-carrier protein] Belongs to the ATP-dependent AMP-binding enzyme family.