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). ATP + H2O + L-tryptophan = AMP + D-tryptophan + diphosphate + H(+) Pigment biosynthesis. NRP synthetases are composed of discrete domains (adenylation (A), thiolation (T) or peptidyl carrier protein (PCP) and condensation (C) domains) which when grouped together are referred to as a single module. Each module is responsible for the recognition (via the A domain) and incorporation of a single amino acid into the growing peptide product. Thus, an NRP synthetase is generally composed of one or more modules and can terminate in a thioesterase domain (TE) that releases the newly synthesized peptide from the enzyme. Occasionally, epimerase (E) domains responsible for L- to D-amino acid conversion are present within the NRP synthetase. IvoA has the following mono-modular architecture: A-T-E-C. Impairs the production of the gray-brown conidiophore pigment and leads to 'ivory' (colorless) conidiophores (PubMed:2126551). Belongs to the NRP synthetase family. Genetic studies provided compelling evidence implicating ivoA in the biosynthesis of N-acetyl-hydroxytryptophan (Ref.3, PubMed:28108400). The proposed acetyltransferase activity of ivoA is however an unlikely fit for a single-module NRPS and further studies showed that ivoA actually catalyzes ATP-dependent unidirectional stereo-inversion of L-tryptophan to D-tryptophan (PubMed:31573806).