Characterization of an orphan biosynthetic gene cluster found in the fungus Aspergillus candidus CBS 102.13 resulted in the discovery of a pyrrolobenzazepine alkaloid, aspcandine (1). The unique molecular scaffold of 1 is synthesized by the nonribosomal peptide synthetase-polyketide synthase hybrid AcdB, which unusually incorporates 3-hydroxy-l-kynurenine as a building block. AcdB subsequently performs one round of chain elongation using malonyl-CoA, which is followed by the chain release to furnish the tricyclic system of 1.

中文翻译：

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天冬氨酸：由真菌非核糖体肽合成酶-聚酮化合物合成酶杂交体合成的吡咯苯并氮杂类生物碱

在真菌Aspergillus candidus CBS 102.13 中发现的孤儿生物合成基因簇的表征导致发现了吡咯苯并氮杂类生物碱 aspcandine ( 1 )。1的独特分子支架是由非核糖体肽合成酶-聚酮化合物合成酶杂合 AcdB 合成的，它不寻常地将 3-羟基-l-犬尿氨酸作为构建单元。AcdB 随后使用丙二酰辅酶A 进行一轮链延长，随后链释放以提供1的三环系统。