biochemical level. Four gene sets, asuA-D, govern the formation and assembly of the asukamycin building blocks: a 3-amino-4-hydroxybenzoic acid core component, a cyclohexane ring, two triene polyketide chains, and a 2-amino-3-hydroxycyclopent-2-enonemoiety to form the intermediate protoasukamycin. AsuE1 and AsuE2 catalyze the conversion of protoasukamycin to 4-hydroxyprotoasukamycin, which is epoxidized at
Asukamycin 是 Manumycin 家族代谢产物的一员,是一种从结节链霉菌亚种中分离出来的抗微生物和潜在的抗肿瘤剂。飞鸟 整个 asukamycin 生物合成基因簇在 Streptomyces lividans 中被克隆、组装和异源表达。生物信息学分析和诱变研究阐明了遗传和生化水平的生物合成途径。四个基因组 asuA-D 控制 asukamycin 构建块的形成和组装:3-氨基-4-羟基苯甲酸核心成分、环己烷环、两个三烯聚酮链和 2-氨基-3-羟基环戊- 2-烯酮部分形成中间体原asukamycin。AsuE1 和AsuE2 催化原asukamycin 转化为4-羟基原asukamycin,4-羟基原asukamycin 被AsuE3 在C5-C6 环氧化为最终产物asukamycin。衍生自 Val、Leu 和 Ile 的支链酰基 CoA 起始单元可以通过聚酮化合物合酶 III
Tandem Enzymatic Oxygenations in Biosynthesis of Epoxyquinone Pharmacophore of Manumycin-type Metabolites
作者:Zhe Rui、Moriah Sandy、Brian Jung、Wenjun Zhang
DOI:10.1016/j.chembiol.2013.05.006
日期:2013.7
Many natural products contain epoxyquinone pharmacophore with unknown biosynthetic mechanisms. Recent genetic analysis of the asukamycin biosynthetic gene cluster proposed enzyme candidates related to epoxyquinone formation for manumycin-type metabolites. Our biochemical studies reveal that 3-amino-4-hydroxyl benzoic acid (3,4-AHBA) precursor is activated and loaded on aryl carrier protein (AsuC12) by ATP-dependent adenylase (AsuA2). AsuE1 and AsuE3, both single-component flavin-dependent monooxygenases, catalyze the exquisite regio- and enantiospecific postpolyketide synthase (PKS) assembly oxygenations. AsuE1 installs a hydroxyl group on the 3,4-AHB ring to form a 4-hydroxyquinone moiety, which is epoxidized by AsuE3 to yield the epoxyquinone functionality. Despite being a single-component monooxygenase, AsuE1 activity is elicited by AsuE2, a pathway-specific flavin reductase. We further demonstrate that the epoxyquinone moiety is critical for anti-MRSA activity by analyzing the bioactivity of various manumycin-type metabolites produced through mutasynthesis.