在核糖体A,P和E位点中的tRNA与23SrRNA的相互作用
1Thimann Laboratories, University of California, Santa Cruz 95064.
Cell
|May 19, 1989
概括
这项研究揭示了转移RNA (tRNA) 在蛋白质合成过程中如何与核糖体RNA (rRNA) 相互作用. 通过tRNA在23SrRNA中的特定核酸保护表明了CCA终端相互作用和抗生素结合点.
科学领域:
- 分子生物学分子生物学
- 生物化学 生物化学
- 结构生物学 结构生物学
背景情况:
- 核糖体对于蛋白质合成至关重要,它将从信使RNA (mRNA) 的遗传信息转化为氨基酸序列.
- 转移RNA (tRNA) 分子向核糖体输送特定的氨基酸,对于准确的翻译至关重要.
- 抗生素可以向核糖体功能,抑制细菌蛋白质合成.
研究的目的:
- 为了研究tRNA和23S核糖体RNA (rRNA) 在A,P和E位点之间的特定相互作用.
- 为了确定23S rRNA中受tRNA结合保护的核酸区域及其功能意义.
- 阐明延长因子Tu (EF-Tu) 在调节tRNA与核糖体相互作用中的作用.
主要方法:
- 在23S rRNA.中对保存核酸进行化学探测.
- 对tRNA与核糖体A,P和E位点结合的保护模式的分析.
- 通过缺乏3'-终端CCA或乙烯基组的修改后tRNA检测保护变化的研究.
- 在EF-Tu.GTP.aminoacyl-tRNA三元复合物的存在下检查保护模式.
主要成果:
- 在23S rRNA中,三组保存的核酸被位于V域附近的基转移酶中心的A,P和E位点的tRNA结合所保护.
- 一些受保护的网站与那些受到抗生素保护的网站重叠,例如氨基醇,这表明药物干扰蛋白质合成的机制.
- 移除tRNA3'-终端的CCA或乙基组取消了特定的保护,证实了tRNA终端与23SrRNA的相互作用.
- EF-Tu.GTP.aminoacyl-tRNA与核糖体结合,防止A位保护直到EF-Tu释放,表明其在调节tRNA相互作用中的作用.
结论:
- tRNA的3'-终端CCA直接与23SrRNA的基转移酶区域中的保存核酸相互作用.
- 在编码子识别过程中,EF-Tu暂时阻止了氨基酸-tRNA 3'终端与核糖体的相互作用,从而促进了翻译校对.
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