在转位核糖体上的tmRNA-SmpB和EF-G复合体
David J F Ramrath1, Hiroshi Yamamoto, Kristian Rother
1Institut für Medizinische Physik und Biophysik, Charite - Universitätsmedizin Berlin, Ziegelstrasse 5-9, 10117 Berlin, Germany.
Nature
|May 25, 2012
概括
细菌核糖体使用转移信使RNA (tmRNA) 和SmpB蛋白来挽救停滞的翻译. 一种新的30S头旋转机制促进了tmRNA转位和mRNA加载非正规途径.
科学领域:
- 分子生物学分子生物学
- 结构生物学 结构生物学
- 微生物学 微生物学
背景情况:
- 细菌核糖体可以在功能不良的信使RNA (mRNA) 上停滞.
- 转移信使RNA (tmRNA) 介导的转译可以拯救这些停滞不前的核糖体.
- 该SmpB蛋白与tmRNA形成复合体,促进其与核糖体的相互作用.
研究的目的:
- 阐明转译过程中tmRNA转位和mRNA加载的结构机制.
- 为了了解核糖体如何适应大型的结构性tmRNA分子.
- 调查EF-G延长因子在这种非正典翻译过程中的作用.
主要方法:
- 低温电子显微镜 (cryo-EM) 用于重建一个化酸停滞的核糖体70S-tmRNA-SmpB-EF-G复合体.
- 高分辨率 (8.3 Å) 结构分析转移后中间体 (TI(POST)).
主要成果:
- 鉴定了30S核糖体头的一个独特的大旋转运动.
- 这种旋转配对tmRNA-SmpB转位到tmRNA的mRNA样域 (MLD) 的加载.
- 在ap/P混合部位观察到TLD-SmpB模块,在pe/E混合部位观察到tRNA(fMet).
结论:
- 30S头旋转器是一个关键机制,可以实现tmRNA转位和MLD加载.
- 这一过程凸显了核糖体的动态和多功能性质.
- 核糖体结构动力学可以重新用于专业的非正规途径,如转译.
相关概念视频
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Sec61 protein conducting channel
In eukaryotes, the translocon complex comprises a core heterotrimeric translocator channel called the Sec61 complex. This channel includes three transmembrane proteins, Sec61α, Sec61β, and Sec61γ, and is the largest subunit of the translocon complex.
Ribosomes
Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that synthesize large quantities of protein—such as secretory cells in the human pancreas—can contain millions of ribosomes.
Ribosome Structure and Assembly
Ribosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome production. Within...
Ribosome Structure and Assembly
Ribosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome production. Within...
Ribosomes
Ribosomes translate genetic information encoded by messenger RNA (mRNA) into proteins. Both prokaryotic and eukaryotic cells have ribosomes. Cells that synthesize large quantities of protein—such as secretory cells in the human pancreas—can contain millions of ribosomes.
Ribosome Structure and Assembly
Ribosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome production. Within...
Ribosome Structure and Assembly
Ribosomes are composed of ribosomal RNA (rRNA) and proteins. In eukaryotes, rRNA is transcribed from genes in the nucleolus—a part of the nucleus that specializes in ribosome production. Within...


