School of Life Sciences, University of Science and Technology of China, Hefei 230026, China; State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China.
College of Pharmacy, Nanjing University of Chinese Medicine, Nanjing 210023, China; State Key Laboratory of Toxicology & Medical Countermeasures, Beijing Institute of Pharmacology & Toxicology, Beijing 100850, China.
Fungal Genet Biol. 2019 Aug;129:7-15. doi: 10.1016/j.fgb.2019.04.004. Epub 2019 Apr 10.
Eupenifeldin, a bistropolone meroterpenoid, was first discovered as an antitumor agent from the fungus Eupenicillium brefeldianum. We also isolated this compound and a new congener from a strain of Phoma sp. (CGMCC 10481), and evaluated their antitumor effects. Eupenifeldin showed potent in vitro anti-glioma activity. This tropolone-humulene-tropolone meroterpenoid could be originated from two units of tropolone orthoquinone methides and a 10-hydroxyhumulene moiety via hetero-Diels-Alder reactions. To explore the biosynthesis of this class of tropolonic sesquiterpenes, the genome of a eupenifeldin-producing Phoma sp. was sequenced and analyzed. The biosynthetic gene cluster of eupenifeldin (eup) was identified and partially validated by genomic analysis, gene disruption, and product analysis. A nonreducing polyketide synthase EupA, a FAD-dependent monooxygenase EupB, and a non-heme Fe (II)-dependent dioxygenase EupC, were identified as the enzymes responsible for tropolone formation. While the terpene cyclase EupE of an unknown family was characterized to catalyze humulene formation, and a cytochrome P450 enzyme EupD was responsible for hydroxylation of humulene. This study sheds light on the biosynthesis of eupenifeldin, and paves the way to further decipher its biosynthetic pathway.
莪坪菲灵，一种双稠酮倍半萜，最初是从真菌大青霉（Eupenicillium brefeldianum）中发现的一种抗肿瘤剂。我们还从青霉属（CGMCC 10481）的一株菌中分离到这种化合物和一个新的同系物，并评价了它们的抗肿瘤活性。莪坪菲灵表现出很强的体外抗神经胶质瘤活性。这种 2-甲基-5-丙基-1,2,3,4-四氢萘-1,4-二酮-5-降蒈烯倍半萜，可能来源于两个 tropolone 邻醌甲叉基和一个 10-羟基葎草烯部分，通过杂 Diels-Alder 反应形成。为了探索这类 tropolonic 倍半萜的生物合成，我们对一株产生莪坪菲灵的青霉属菌进行了基因组测序和分析。通过基因组分析、基因敲除和产物分析，鉴定并部分验证了莪坪菲灵（eup）的生物合成基因簇。鉴定了一个非还原型聚酮合酶 EupA、一个 FAD 依赖型单加氧酶 EupB 和一个非血红素 Fe（II）依赖型双加氧酶 EupC，它们负责 tropolone 的形成。而一个未知家族的萜烯环化酶 EupE 被鉴定为催化葎草烯形成的酶，一个细胞色素 P450 酶 EupD 负责葎草烯的羟化。本研究阐明了莪坪菲灵的生物合成途径，为进一步解析其生物合成途径奠定了基础。
