Nonribosomal peptide synthetase; part of the gene cluster that mediates the biosynthesis of an unusual class of epipolythiodioxopiperazines (ETPs) lacking the reactive thiol group important for toxicity (PubMed:27390873). Firstly, L-tyrosine is prenylated by tcpD, before undergoing condensation with L-glycine in a reaction catalyzed by the NRPS tcpP leading to the diketopiperazine (DKP) backbone (PubMed:27390873). Afterwards the alpha-carbon of tyrosine is oxidized by the cytochrome P450 tcpC to form a hydroxyl group (PubMed:27390873). However, in contrast other ETP biosynthesis pathways studied so far, tcpC is not able to bishydroxylate the DKP at both alpha-carbon positions, but hydroxylates the alpha-carbon of the tyrosine part and the nitrogen of the glycine part (PubMed:27390873). The next steps involve an alpha,beta-elimination reaction catalyzed by tcpI, a methylation by the methyltransferase tcpN the action of the four enzyme cascade tcpG/K/J/I (PubMed:27390873). Due to a dysfunctional cytochrome P450 monooxygenase tcpC, the pathway leads to the biosynthesis of probable non-toxic metabolites lacking the reactive thiol group (PubMed:27390873). Secondary metabolite biosynthesis. Expression is positively regulated by the thioclapurine cluster-specific transcription factor tcpZ (PubMed:27390873). 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 (By similarity). Each module is responsible for the recognition (via the A domain) and incorporation of a single amino acid into the growing peptide product (By similarity). 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 (By similarity). Occasionally, epimerase (E) domains (responsible for L- to D-amino acid conversion) are present within the NRP synthetase (By similarity). NRPS10 has the foolowing architecture: A-T-C-A-T-C (PubMed:27390873). Belongs to the NRP synthetase family.