The saprotrophic filamentous fungus Myrothecium inundatum represents a chemically underexplored ascomycete with a high number of putative biosynthetic gene clusters in its genome. Here, we present new linear lipopeptides from nongenetic gene activation experiments using nutrient and salt variations. Metabolomics studies revealed four myropeptins, and structural analyses by NMR, HRMS, Marfey’s analysis, and ECD assessment for their helical properties established their absolute configuration. A myropeptin biosynthetic gene cluster in the genome was identified. The myropeptins exhibit general nonspecific toxicity against all cancer cell lines in the NCI-60 panel, larval zebrafish with EC₅₀ concentrations of 5–30 μM, and pathogenic bacteria and fungi (MICs of 4–32 μg/mL against multidrug-resistant S. aureus and C. auris). In vitro hemolysis, cell viability, and ionophore assays indicate that the myropeptins target mitochondrial and cellular membranes, inducing cell depolarization and cell death. The toxic activity is modulated by the length of the lipid side chain, which provides valuable insight into their structure–activity relationships.

中文翻译：

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代谢组学指导下 Myrothecium inundatum 中 Myropeptins C-E 的发现、分离、结构解析和生物活性


腐生丝状真菌Myrothecium inundatum代表了一种化学上尚未充分研究的子囊菌，其基因组中具有大量假定的生物合成基因簇。在这里，我们利用营养和盐的变化，从非遗传基因激活实验中展示了新的线性脂肽。代谢组学研究揭示了四种肌肽蛋白，通过 NMR、HRMS、Marfey 分析和 ECD 评估对其螺旋特性进行结构分析，确定了它们的绝对构型。鉴定出基因组中的肌肽素生物合成基因簇。肌肽素对 NCI-60 组中的所有癌细胞系、EC ₅₀浓度为 5-30 μM 的幼虫斑马鱼以及致病细菌和真菌（针对多重耐药金黄色葡萄球菌的 MIC 为 4-32 μg/mL）表现出一般非特异性毒性。金黄色葡萄球菌和耳念珠菌）。体外溶血、细胞活力和离子载体测定表明肌肽素靶向线粒体和细胞膜，诱导细胞去极化和细胞死亡。毒性活性由脂质侧链的长度调节，这为了解其结构-活性关系提供了有价值的见解。