Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Boston, MA 02115, USA.
ACS Chem Biol. 2013 Apr 19;8(4):741-8. doi: 10.1021/cb3006787. Epub 2013 Feb 6.
Ardeemins are hexacyclic peptidyl alkaloids isolated from Aspergillus fischeri as agents that block efflux of anticancer drugs by MultiDrug Resistance (MDR) export pumps. To evaluate the biosynthetic logic and enzymatic machinery for ardeemin framework assembly, we sequenced the A. fischeri genome and identified the ardABC gene cluster. Through both genetic deletions and biochemical characterizations of purified ArdA and ArdB we show this ArdAB enzyme pair is sufficient to convert anthranilate (Ant), L-Ala, and L-Trp to ardeemin. ArdA is a 430 kDa trimodular nonribosomal peptide synthase (NRPS) that converts the three building blocks into a fumiquinazoline (FQ) regioisomer termed ardeemin FQ. ArdB is a prenyltransferase that takes tricyclic ardeemin FQ and dimethylallyl diphosphate to the hexacyclic ardeemin scaffold via prenylation at C2 of the Trp-derived indole moiety with intramolecular capture by an amide NH of the fumiquinazoline ring. The two-enzyme ArdAB pathway reveals remarkable efficiency in construction of the hexacyclic peptidyl alkaloid scaffold.
阿得明是从曲霉属真菌 Aspergillus fischeri 中分离得到的六环肽基生物碱，可作为多药耐药 (MDR) 外排泵阻断抗癌药物外排的药物。为了评估阿得明框架组装的生物合成逻辑和酶机制，我们对 A. fischeri 基因组进行了测序，并鉴定了 ardABC 基因簇。通过对 ArdA 和 ArdB 的遗传缺失和生化特性的研究，我们证明了 ArdAB 酶对将邻氨基苯甲酸 (Ant)、L-Ala 和 L-Trp 转化为阿得明是足够的。ArdA 是一个 430 kDa 的三模块非核糖体肽合酶 (NRPS)，可将这三个构建块转化为一种称为阿得明 FQ 的福喹啉 (FQ) 区域异构体。ArdB 是一种 prenyltransferase，可通过将三环阿得明 FQ 和二甲基烯丙基二磷酸与来自 Trp 的吲哚部分的 C2 进行 prenylation，将其转化为六环阿得明支架，通过福喹啉环的酰胺 NH 进行分子内捕获。双酶 ArdAB 途径在构建六环肽基生物碱支架方面表现出显著的效率。
