Nonribosomal peptide synthase; part of the gene cluster that mediates the biosynthesis of peramine, a pyrrolopyrazine synthesized in association with the grass host that protects the plant from insect herbivory (PubMed:16091042). The single multifunctional NRPS perA seems to be responsible for all catalytic steps in the biosynthesis of peramine (PubMed:16091042). The condensation domain of perA is proposed to catalyze formation of a peptide bond between 1-pyrroline-5-carboxylate and arginine (PubMed:16091042). The methylation domain of perA would catalyze the N-methylation of the alpha-amino group of arginine (PubMed:16091042). The reductase domain is proposed to be responsible for reduction of the thioester and the cyclization to form an iminium ion resulting in release from the peptide synthetase (PubMed:16091042). Deprotonation of this intermediate and oxidation of the pyrroline ring would give rise to peramine (PubMed:16091042). This final oxidation to give the pyrrole functionality may be spontaneous (PubMed:16091042). Expression is down-regulated when the stress-activated mitogen-activated protein kinase (sakA) is deleted (PubMed:20519633). 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, methyltransferase domains (responsible for amino acid methylation) are present within the NRP synthetase (By similarity). PerA has the following architecture: A-T-C-A-Met-T-TE (PubMed:16091042). Impairs the production of peramine and results in host susceptibility to insect herbivory (PubMed:16091042). Belongs to the NRP synthetase family.