Nonribosomal peptide synthetase; part of the pathway that mediates the biosynthesis of the gray-brown conidiophore pigment (PubMed:23617571, PubMed:28108400). The first step of the pathway is performed by the nonribosomal peptide synthetase ivoA that catalyzes ATP-dependent unidirectional stereoinversion of L-tryptophan to D-tryptophan with complete conversion (PubMed:31573806). While the stereoinversion is catalyzed by the epimerization (E) domain of ivoA, the terminal condensation (C) domain stereoselectively hydrolyzes D-tryptophanyl-S-phosphopantetheine thioester and thus represents a non-canonical C domain function (PubMed:31573806). D-tryptophan is acetylated, probably by an endogenous acetyltransferase (Probable). N-acetyltryptophan is further 6-hydroxylated into N-acetyl-6-hydroxytryptophan (AHT) by the cytochrome P450 monooxygenase ivoC (PubMed:28108400). N-acetyl-6-hydroxytryptophan is substrate of the N-acetyl-6-hydroxytryptophan oxidase ivoB to produce the gray-brown conidiophore pigment (PubMed:2126551, PubMed:28108400, Ref.3). Pigment biosynthesis. Belongs to the cytochrome P450 family.