Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; The SJ Yan and HJ Mao Laboratory of Chemical Biology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
Department of Molecular Biology and Genetics, Johns Hopkins School of Medicine, and Howard Hughes Medical Institute, Baltimore, MD 21205, USA.
Cell Chem Biol. 2017 May 18;24(5):605-613.e5. doi: 10.1016/j.chembiol.2017.04.006. Epub 2017 Apr 27.
Protein synthesis plays an essential role in cell proliferation, differentiation, and survival. Inhibitors of eukaryotic translation have entered the clinic, establishing the translation machinery as a promising target for chemotherapy. A recently discovered, structurally unique marine sponge-derived brominated alkaloid, (-)-agelastatin A (AglA), possesses potent antitumor activity. Its underlying mechanism of action, however, has remained unknown. Using a systematic top-down approach, we show that AglA selectively inhibits protein synthesis. Using a high-throughput chemical footprinting method, we mapped the AglA-binding site to the ribosomal A site. A 3.5 Å crystal structure of the 80S eukaryotic ribosome from S. cerevisiae in complex with AglA was obtained, revealing multiple conformational changes of the nucleotide bases in the ribosome accompanying the binding of AglA. Together, these results have unraveled the mechanism of inhibition of eukaryotic translation by AglA at atomic level, paving the way for future structural modifications to develop AglA analogs into novel anticancer agents.
蛋白质合成在细胞增殖、分化和存活中起着至关重要的作用。真核翻译抑制剂已进入临床，使翻译机制成为化疗的一个有前途的靶点。最近发现的一种结构独特的海洋海绵衍生的溴化生物碱（-）-agelastatin A（AglA）具有很强的抗肿瘤活性。然而，其作用机制仍不清楚。我们采用系统的自上而下的方法，证明 AglA 选择性地抑制蛋白质合成。我们使用高通量化学足迹法将 AglA 的结合位点映射到核糖体 A 位。获得了来自酿酒酵母的 80S 真核核糖体与 AglA 复合物的 3.5Å 晶体结构，揭示了伴随 AglA 结合的核糖体中核苷酸碱基的多种构象变化。这些结果共同揭示了 AglA 抑制真核翻译的机制，在原子水平上为未来的结构修饰将 AglA 类似物开发成新型抗癌药物铺平了道路。
