Watanabe A, Fujii I, Tsai H, Chang Y C, Kwon-Chung K J, Ebizuka Y
Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Japan.
FEMS Microbiol Lett. 2000 Nov 1;192(1):39-44. doi: 10.1111/j.1574-6968.2000.tb09356.x.
Conidial pigment biosynthesis is an important virulence factor in Aspergillus fumigatus, a human fungal pathogen. Involvement of DHN-melanin pathway in the biosynthesis of A. fumigatus conidial pigment implies that the Alb1p polyketide synthase (PKS) is a 1,3,6, 8-tetrahydroxynaphthalene (T4HN) synthase. The Alb1p, however, shows higher sequence similarity to a naphthopyrone synthase than to a T4HN synthase. To clarify the function of Alb1p, the alb1 gene was overexpressed in a heterologous host Aspergillus oryzae. The Alb1p PKS product in this heterologous expression system was identified as heptaketide naphthopyrone instead of pentaketide T4HN. The data suggest that Alb1p is a naphthopyrone synthase.
分生孢子色素生物合成是人类真菌病原体烟曲霉中的一种重要毒力因子。DHN-黑色素途径参与烟曲霉分生孢子色素的生物合成，这意味着Alb1p聚酮合酶（PKS）是一种1,3,6,8-四羟基萘（T4HN）合酶。然而，Alb1p与萘并吡喃酮合酶的序列相似性高于与T4HN合酶的序列相似性。为了阐明Alb1p的功能，alb1基因在异源宿主米曲霉中过表达。在这个异源表达系统中，Alb1p PKS产物被鉴定为庚酮萘并吡喃酮，而不是戊酮T4HN。数据表明Alb1p是一种萘并吡喃酮合酶。
