Cyclic peptide natural products have evolved to exploit diverse protein targets, many of which control essential cellular processes. Inspired by a series of cyclic peptides with partially elucidated structures, we designed synthetic variants of ternatin, a cytotoxic and anti-adipogenic natural product whose molecular mode of action was unknown. The new ternatin variants are cytotoxic toward cancer cells, with up to 500-fold greater potency than ternatin itself. Using a ternatin photo-affinity probe, we identify the translation elongation factor-1A ternary complex (eEF1A·GTP·aminoacyl-tRNA) as a specific target and demonstrate competitive binding by the unrelated natural products, didemnin and cytotrienin. Mutations in domain III of eEF1A prevent ternatin binding and confer resistance to its cytotoxic effects, implicating the adjacent hydrophobic surface as a functional hot spot for eEF1A modulation. We conclude that the eukaryotic elongation factor-1A and its ternary complex with GTP and aminoacyl-tRNA are common targets for the evolution of cytotoxic natural products.
环肽
天然产物的发展利用了多种蛋白质靶标,其中许多靶标控制着重要的细胞过程。受一系列结构已部分阐明的环肽的启发,我们设计出了具有细胞毒性和抗脂肪生成作用的天然产品 ternatin 的合成变体,而这种天然产品的分子作用模式尚不清楚。新的燕麦素变体对癌细胞具有细胞毒性,其效力比燕麦素本身高出 500 倍。利用特纳丁的光亲和探针,我们确定了翻译延伸因子-1A 三元复合物(eEF1A-GTP-
氨基酰-tRNA)为特异性靶标,并证明了与之无关的
天然产物--didemnin 和 cytotrienin 的竞争性结合。eEF1A 结构域 III 的突变阻止了 ternatin 的结合,并使其对细胞毒性效应产生抗性,这表明邻近的疏
水表面是 eEF1A 调节的功能热点。我们的结论是,真核
生物伸长因子-1A及其与 GTP 和
氨基酰-tRNA 的三元复合物是细胞毒性
天然产物进化的共同目标。