Comparative characterization of fungal anthracenone and naphthacenedione biosynthetic pathways reveals an α-hydroxylation-dependent Claisen-like cyclization catalyzed by a dimanganese thioesterase.
Comparative characterization of fungal anthracenone and naphthacenedione biosynthetic pathways reveals an α-hydroxylation-dependent Claisen-like cyclization catalyzed by a dimanganese thioesterase.
复制标题
DOI：
10.1021/ja206906d
复制
发表时间：
2011-10-05
影响因子：
15
通讯作者：
Tang, Yi
中科院分区：
文献类型：
--
作者：
Li, Yanran;Chooi, Yit-Heng;Sheng, Yuewei;Valentine, Joan S.;Tang, Yi
线性四环TAN-1612（1）和BMS-192548（2）是从不同的丝状真菌菌株中分离得到的，并已被分别检测为潜在的神经肽Y和神经激肽-1受体拮抗剂。虽然近年来真菌芳香族聚酮的生物合成引起了人们的极大兴趣，但这种含萘并二酮产物的生物合成机制尚未建立。利用靶向基因组挖掘方法，我们首先定位了尼日尔曲霉ATCC 1015中负责1生物合成的ADA基因簇。1和ADA通路之间的连接通过Zn 2Cys 6型通路特异性转录调节因子阿达尔的过表达和随后的基因表达分析来验证。在ada基因簇中编码的酶与已知的与蒽醌曲霉素3生物合成相关的apt途径具有高度的序列相似性。随后在酿酒酵母中通过异源途径重建对这两个高度同源的基因簇进行了比较研究，发现了一种新的α-羟基化依赖性Claisen环化级联反应，该级联反应涉及黄素依赖性单加氧酶（FMO）和双功能金属-β-内酰胺酶型硫酯酶（MβL-TE），黄素依赖性单加氧酶（FMO）可将ACP结合的聚酮化合物的α-碳羟基化。双功能MβL-TE在α-羟基化后催化第四环环化得到萘并二酮骨架，而在不存在α-羟基化的情况下水解释放蒽酮产物。通过体外生化表征和金属分析，我们证实apt MβL-TE是一种双锰酶，并且需要两种Mn 2+阳离子才能达到所观察到的活性。MβL-TE是聚酮生物合成中TE的第一个例子，其催化Claisen样缩合而没有α/β水解酶折叠，并且与底物不形成共价键。这些机理特征对四环并苯二酮类化合物在真菌中的生物合成具有普遍意义。
The linear tetracyclic TAN-1612 (1) and BMS-192548 (2) were isolated from different filamentous fungal strains, and have been examined as potential neuropeptide Y and neurokinin-1 receptor antagonist respectively. Although the biosynthesis of fungal aromatic polyketides has attracted much interest in recent years, the biosynthetic mechanism for such naphthacenedione-containing products has not been established. Using a targeted genome mining approach, we first located the ada gene cluster responsible for the biosynthesis of 1 in Aspergillus niger ATCC 1015. The connection between 1 and the ada pathway was verified through overexpression of the Zn2Cys6-type pathway-specific transcriptional regulator AdaR and subsequent gene expression analysis. The enzymes encoded in the ada gene cluster share high sequence similarities to the known apt pathway linked to the biosynthesis of anthraquinone asperthecin 3. Subsequent comparative investigation of these two highly homologous gene clusters by heterologous pathway reconstitution in Saccharomyces cerevisiae revealed a novel α-hydroxylation-dependent Claisen cyclization cascade, which involves a flavin-dependent monooxygenase (FMO) that hydroxylates the α-carbon of an ACP-bound polyketide and a bifunctional metallo-β-lactamase-type thioesterase (MβL-TE). The bifunctional MβL-TE catalyzes the fourth ring cyclization to afford the naphthacenedione scaffold upon α-hydroxylation, while performs hydrolytic release of an anthracenone product in the absence of α-hydroxylation. Through in vitro biochemical characterizations and metal analyses, we verified that the apt MβL-TE is a dimanganese enzyme and requires both Mn2+ cations for the observed activities. The MβL-TE is the first example of TE in polyketide biosynthesis that catalyzes the Claisen-like condensation without an α/β hydrolase fold and forms no covalent bond with the substrate. These mechanistic features should be general to the biosynthesis of tetracyclic naphthacenedione compounds in fungi.
登录
查看更多内容
DOI：
10.1038/nrmicro2465
发表时间：
2010-12
期刊：
Nature reviews. Microbiology
影响因子：
--
作者：
通讯作者：
--
影响因子：
4.9
作者：
Bailey, Andrew M.;Cox, Russell J.;Skellam, Elizabeth
通讯作者：
Skellam, Elizabeth
影响因子：
14.8
作者：
Bergmann, Sebastian;Schuemann, Julia;Hertweck, Christian
通讯作者：
Hertweck, Christian
影响因子：
3.2
作者：
Chen, Yihua;Fan, Keqiang;Yang, Keqian
通讯作者：
Yang, Keqian
影响因子：
18.3
作者：
Das, Abhirup;Khosla, Chaitan
通讯作者：
Khosla, Chaitan