FAD-dependent monooxygenase; part of the gene cluster that mediates the biosynthesis of the benzazepine alkaloid nanangelenin A which contains an unprecedented 3,4-dihydro-1-benzazepine-2,5-dione-N-prenyl-N-acetoxy-anthranilamide scaffold (PubMed:32182055). The first step of nanangelenin biosynthesis is catalyzed by the indoleamine 2,3-dioxygenase nanC which produces N-formyl-kynurenine through the catabolism of tryptophan (PubMed:32182055). The two-module NRPS nanA then utilizes anthranilate (Ant) and L-kynurenine (L-Kyn) to assemble the dipeptide product nanangelenin B (PubMed:32182055). The first adenylation domain of nanA (A1) loads anthranilate onto the T1 domain, while A2 loads kynurenine, generated through spontaneous nonenzymatic deformylation of the nanC-supplied N-formyl-kynurenine (PubMed:32182055). The peptide bond formation between the tethered amino acids is catalyzed by the first condensation domain (C1) between anthranilate's carbonyl carbon and kynurenine's aliphatic primary amine (PubMed:32182055). The second C domain (C2) catalyzes the final cyclization event between the aromatic amine of kynurenine and the tethered carbonyl carbon, yielding nanangelenin B (PubMed:32182055). The terminal T3 domain enhances the catalytic efficiency of C2, suggesting the T2-tethered Ant-L-Kyn is transferred to T3 prior to cyclization by C2 (PubMed:32182055). Once released from nanA, nanangelenin B is then prenylated by the prenyltransferase nanD to form nanangelenin C (PubMed:32182055). Nanangelenin C is then N-hydroxylated by the FAD-dependent monooxygenase nanF and further acetylated by the acetyltransferase nanB to yield nanangelenin F (PubMed:32182055). Finally, the N-methyltransferase nanE methylates the amide nitrogen of 1-benzazepine to convert nanangelenin F into nanangelenin A (PubMed:32182055). NanE is also able to methylate most of the intermediates of the pathway such as nanangelenin B and nanangelenin C to produce nanangelenin D and nanangelenin E, respectively (PubMed:32182055). Secondary metabolite biosynthesis. Belongs to the paxM FAD-dependent monooxygenase family.