Lee Seoung Rak, Dayras Marie, Fricke Janis, Guo Huijuan, Balluff Sven, Schalk Felix, Yu Jae Sik, Jeong Se Yun, Morgenstern Bernd, Slippers Bernard, Beemelmanns Christine, Kim Ki Hyun
School of Pharmacy, Sungkyunkwan University, Suwon, 16419, Republic of Korea.
College of Pharmacy and Research Institute for Drug Development, Pusan National University, Busan, 46241, Republic of Korea.
Commun Chem. 2024 Jun 7;7(1):129. doi: 10.1038/s42004-024-01210-6.
Fungi constitute the Earth's second most diverse kingdom, however only a small percentage of these have been thoroughly examined and categorized for their secondary metabolites, which still limits our understanding of the ecological chemical and pharmacological potential of fungi. In this study, we explored members of the co-evolved termite-associated fungal genus Xylaria and identified a family of highly oxygenated polyketide-terpene hybrid natural products using an MS/MS molecular networking-based dereplication approach. Overall, we isolated six no yet reported xylasporin derivatives, of which xylasporin A (1) features a rare cyclic-carbonate moiety. Extensive comparative spectrometric (HRMS) and spectroscopic (1D and 2D NMR) studies allowed to determine the relative configuration across the xylasporin family, which was supported by chemical shift calculations of more than 50 stereoisomers and DP4+ probability analyses. The absolute configuration of xylasporin A (1) was also proposed based on TDDFT-ECD calculations. Additionally, we were able to revise the relative and absolute configurations of co-secreted xylacremolide B produced by single x-ray crystallography. Comparative genomic and transcriptomic analysis allowed us to deduce the putative biosynthetic assembly line of xylasporins in the producer strain X802, and could guide future engineering efforts of the biosynthetic pathway.
真菌是地球上第二大多样性的生物界,然而,其中只有一小部分因其次生代谢产物而得到了彻底的研究和分类,这仍然限制了我们对真菌的生态化学和药理潜力的理解。在本研究中,我们探索了与白蚁共同进化的真菌属——炭角菌属的成员,并使用基于串联质谱分子网络的去重复方法鉴定了一类高度氧化的聚酮-萜类杂合天然产物。总体而言,我们分离出了六种尚未报道的木孢菌素衍生物,其中木孢菌素A(1)具有罕见的环状碳酸酯部分。广泛的对比光谱分析(高分辨质谱)和光谱分析(一维和二维核磁共振)研究确定了木孢菌素家族的相对构型,这得到了50多种立体异构体的化学位移计算和DP4+概率分析的支持。木孢菌素A(1)的绝对构型也基于含时密度泛函理论-电子圆二色谱计算提出。此外,我们能够通过单晶X射线晶体学修正共同分泌的木霉内酯B的相对和绝对构型。比较基因组学和转录组学分析使我们能够推断出生产菌株X802中木孢菌素的假定生物合成装配线,并可为未来生物合成途径的工程改造提供指导。