整体冷电磁场阐明了翻译准确性的机制
Anna B Loveland1, Gabriel Demo1, Nikolaus Grigorieff2
1RNA Therapeutics Institute, Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, 368 Plantation Street, Worcester, Massachusetts 01605, USA.
Nature
|May 25, 2017
概括
精确的基因翻译依赖于核糖体的精确mRNA解码. 这项研究揭示了核糖体如何区分正确的 (同源) 和不正确的 (近同源) 转移RNA的结构机制,确保了忠实的蛋白质合成.
科学领域:
- 分子生物学
- 结构生物学
- 遗传学
背景情况:
- 基因翻译需要通过核糖体准确解码信使RNA (mRNA).
- 这种解码忠实性的结构基础,特别是相关氨基酸转移RNAs (tRNAs) 的选择,尚未完全理解.
- 延长因子Tu (EF-Tu) 在将氨基酸tRNA输送到核糖体中起着至关重要的作用.
研究的目的:
- 阐明由核糖体进行准确的mRNA解码的结构机制.
- 在翻译启动过程中区分同源与近同源tRNA选择的结构途径.
- 了解EF-Tu在氨基酸-tRNA适应中的作用.
主要方法:
- 核糖体复合体的高分辨率结构分析.
- 电子显微镜 (Cryo-EM) 用于可视化结构组合.
- 通过EF- Tu传递的同源和近同源tRNA与核糖体相互作用的表征.
主要成果:
- 相关和近相关的tRNA最初探索一个开放的30S核糖体子单元.
- 一个特定的核酸构造 (G530) 稳定了相关的子-子螺旋,启动了解码中心的关闭 ("锁定").
- 这种关闭对接EF-Tu,激活GTP水解并使tRNA适应,这一过程在近同类复合体中受到阻碍.
结论:
- 这项研究揭示了同源和近同源tRNA预适应的不同结构途径.
- G530核酸构造作为解码准确性的关键检查点.
- 这项工作为核糖体在蛋白质合成过程中选择正确的氨基酸tRNA的准确性提供了结构基础.
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