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退化的tRNA身份代码的结构基础以及人类线粒体tRNA识别中的双模特性的演变
Bernhard Kuhle1,2, Marscha Hirschi3, Lili K Doerfel3
1Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, 92037, USA. bkuhle@scripps.edu.
Nature communications
|August 9, 2023
概括
线粒体tRNAs在突变压力下演变,但人类线粒体seryl-tRNA合成酶识别了两个不同的tRNAs. 这种酶使用双模读出机制,展示了分子识别中的进化创新.
科学领域:
- 分子生物学分子生物学
- 进化生物学 进化生物学
- 生物化学 生物化学
背景情况:
- 动物线粒体基因表达需要核编码的氨基酸-tRNA合成酶和线粒体编码的tRNA之间的相互作用.
- 线粒体tRNAs (mtRNAs) 面临着强大的突变压力,而选择维持了它们的基本功能,创造了进化紧张.
研究的目的:
- 研究单个氨基酸-tRNA合成酶对分离的线粒体tRNAs识别背后的分子机制.
- 了解进化压力如何塑造线粒体蛋白-RNA相互作用中的特异性.
主要方法:
- 电子显微镜 (cryo-EM) 用于确定人类线粒体-tRNA合成酶 (mSerRS) 与mtRNASer(UGA)的结构.
- 在mSerRS-mtRNASer(UGA)和mSerRS-mtRNASer(GCU)复合体之间进行结构和功能比较.
主要成果:
- 人类的mSerRS识别了两种高度分离的线粒体序列-tRNA异受体,mtRNASer(UGA)和mtRNASer(GCU).
- 这些mtRNA缺乏保存的结构或序列动机,无法被mSerRS.
- mSerRS采用双模读出机制,利用单个蛋白质表面来识别每个mtRNA特有的退化特征.
结论:
- mtRNAs的突变侵蚀推动了新的分子间特异性规则的演变.
- 一个单一的合成酶可以通过可适应的识别机制来容纳功能上相当但结构上不同的tRNA.
- 这突显了进化创新在维持重要的线粒体功能,尽管高突变率.
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