Ophiobolins are a group of sesterterpenoids with a 5-8-5 tricyclic skeleton. They exhibit a significant cytotoxicity and present potential medicinal prospects. However, the biosynthesis and transport mechanisms of these valuable compounds have not been fully resolved. Herein, based on a transcriptome analysis, gene inactivation, heterologous expression and feeding experiments, we fully explain the biosynthesis pathway of ophiobolin K in Aspergillus ustus 094102, especially proved to be an unclustered oxidase OblCAu that catalyzes dehydrogenation at the site of C16 and C17 of both ophiobolin F and ophiobolin C. We also find that the intermediate ophiobolin C and final product ophiobolin K could be transported into a space between the cell wall and membrane by OblDAu to avoid the inhibiting of cell growth, which is proved by a fluorescence observation of the subcellular localization and cytotoxicity tests. This study completely resolves the biosynthesis mechanism of ophiobolins in strain A. ustus 094102. At the same time, it is revealed that the burden of strain growth caused by the excessive accumulation and toxicity of secondary metabolites is closely related to compartmentalized biosynthesis.

中文翻译：

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Aspergillus ustus 094102 中蛇毒蛋白的生物合成和运输

Ophiobolins 是一组具有 5-8-5 三环骨架的酯萜类化合物。它们表现出显着的细胞毒性并具有潜在的药用前景。然而，这些有价值的化合物的生物合成和运输机制尚未完全解决。在此，基于转录组分析、基因失活、异源表达和喂养实验，我们充分解释了 Aspergillus ustus 094102 中蛇麻黄素 K 的生物合成途径，特别是证明了它是一种非簇状氧化酶 OblCAu，可催化 C16 和 C17 位点的脱氢。 ophiobolin F 和 ophiobolin C。我们还发现 OblDAu 可以将中间体 ophiobolin C 和最终产物 ophiobolin K 转运到细胞壁和膜之间的空间中，以避免抑制细胞生长，亚细胞定位和细胞毒性试验的荧光观察证明了这一点。本研究彻底解决了菌株A.ustus 094102中蛇毒蛋白的生物合成机制，同时揭示了次生代谢产物过度积累和毒性导致的菌株生长负担与区室化生物合成密切相关。