Abstract：
Fungal azaphilones have attracted widespread attention due to their significant potential as sources of food pigments and pharmaceuticals. Genome mining and gene cluster activation represent powerful tools and strategies for discovering novel natural products and bioactive molecules. Here, a putative azaphilone biosynthetic gene cluster lut from the endophytic fungus Talaromyces sp. was identified through genome mining. By overexpressing the pathway-specific transcription factor LutB, five new sclerotiorin-type azaphilones (1, 6, 8, and 10-11) together with seven known analogues (2-5, 7, 9, 12) were successfully produced. Compounds 8 and 9 exhibited antibacterial activity against Bacillus subtilis with MIC values of 64 and 16 μg/mL, respectively. Compound 11 showed cytotoxic activity against HCT116 and GES-1 with IC50 values of 10.9 and 4.9 μM, respectively, while 1, 4, 5, and 7-10 showed no obvious cytotoxic activity. Gene inactivation experiments confirmed the role of the lut cluster in the production of compounds 1-12. Subsequent feeding experiments unveiled the novel functional diversity of the dual megasynthase system. Furthermore, a LutC-LutD binary oxidoreductase system was discovered, and in combination with DFT calculations, the basic biosynthetic pathway of the sclerotiorin-type azaphilones was characterized. This study provided a good example for the discovery of new azaphilones and further uncovered the biosynthesis of these compounds.
摘要：
真菌氮杂吡酮由于其作为食品色素和药物来源的巨大潜力而引起了广泛的关注。基因组挖掘和基因簇激活代表了发现新的天然产物和生物活性分子的强大工具和策略。这里,来自内生真菌Talaromycessp。是通过基因组挖掘鉴定的。通过过表达通路特异性转录因子LutB,成功制备了5种新的硬化素型氮杂菲酮(1,6,8和10-11)和7种已知的类似物(2-5,7,9,12).化合物8和9对枯草芽孢杆菌具有抗菌活性,MIC值分别为64和16μg/mL,分别。化合物11显示对HCT116和GES-1的细胞毒性活性,IC50值为10.9和4.9μM,分别,而1、4、5和7-10没有明显的细胞毒活性。基因失活实验证实了lut簇在化合物1-12产生中的作用。随后的喂养实验揭示了双megasynthase系统的新型功能多样性。此外，LutC-LutD二元氧化还原酶系统被发现，并结合DFT计算，对硬化因子型氮杂菲酮的基本生物合成途径进行了表征。这项研究为发现新的氮杂吡酮提供了一个很好的例子，并进一步揭示了这些化合物的生物合成。
