Aspcandine: A Pyrrolobenzazepine Alkaloid Synthesized by a Fungal Nonribosomal Peptide Synthetase-Polyketide Synthase Hybrid.

Characterization of an orphan biosynthetic gene cluster found in the fungus CBS 102.13 resulted in the discovery of a pyrrolobenzazepine alkaloid, aspcandine (). The unique molecular scaffold of is synthesized by the nonribosomal peptide synthetase-polyketide synthase hybrid AcdB, which unusually incorporates 3-hydroxy-l-kynurenine as a building block.