通过转移RNA lysidine synthetase确保的翻译忠实性的结构基础
Kotaro Nakanishi1, Luc Bonnefond, Satoshi Kimura
1Department of Biological Information, Graduate School of Bioscience and Biotechnology, Tokyo Institute of Technology, Yokohama, Kanagawa 225-8501, Japan.
Nature
|October 23, 2009
概括
细菌tRNA通过lysidine合成酶 (TilS) 的修饰发生在前体tRNA上,防止 metionin的错误整合. 这确保了通过修改tRNA(Ile2) 在它成熟之前,通过精确的异黄素翻译.
科学领域:
- 分子生物学分子生物学
- 生物化学 生物化学
- 遗传学 是一个遗传学.
背景情况:
- 转移RNA (tRNA) 的成熟涉及多个处理步骤,包括核酸修饰.
- lysidine合成酶 (TilS) 在tRNA中将cytidine修改为lysidine (Ile2),将其氨基酸特异性从氨酸转换为isoleucine.
- 一个潜在的陷存在于 metionyl-tRNA合成酶 (MetRS) 可以误电前体tRNA ((Ile2) 与 metionin.
研究的目的:
- 阐明细菌避免 metionin 错误地被纳入异氨酸编码子中的机制.
- 调查tRNA的基质特异性和修改时间{Ile2} lysidine合成酶 (TilS).
主要方法:
- 从缺乏RNase-E的埃舍里希亚大肠杆菌中分离和分析前体tRNA(Ile2).
- 对前体和成熟tRNATilS活性的动态分析 (Ile2).
- 对TilS-tRNA相互作用的X射线晶体学和突变分析.
主要成果:
- 在前体tRNA (Ile2) 中发现了lysidine修饰,而缺乏这种修饰的成熟tRNA (Ile2) 并没有被检测到.
- 对于前体和成熟tRNA,TilS的催化效率相似.
- TilS通过广泛的相互作用和域移动专门识别前体tRNA的L形结构,防止MetRS结合.
结论:
- TilS修改了前体tRNA ((Ile2),从而防止其被MetRS误充,并确保了准确的异氨酸翻译.
- 提尔S对前体tRNA的特定识别 (Ile2) 对于保持翻译忠实性至关重要.
- 这项研究强调了在tRNA生物发生过程中在前体水平上纳入特定核酸修饰的重要性.
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