核糖体动力学和tRNA运动通过时间解析的电子冷显微镜
Niels Fischer1, Andrey L Konevega, Wolfgang Wintermeyer
13D Electron Cryomicroscopy Group, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
Nature
|July 16, 2010
概括
这项研究使用冷电子显微镜 (cryo-EM) 可视化了蛋白质合成转位期间的转移RNA (tRNA) 运动. 它揭示了核糖体如何作为布朗机器,将热能与指导的tRNA运动相合.
科学领域:
- 分子生物学分子生物学
- 结构生物学 结构生物学
- 生物物理学的生物物理.
背景情况:
- 蛋白质合成涉及复杂的核糖体转移RNA (tRNA) 在转位过程中的重排.
- 了解核糖体内的tRNA动态对于破译基因表达机制至关重要.
研究的目的:
- 在转位过程中可视化和描述tRNA通过核糖体的运动.
- 阐明控制tRNA转位的结构变化和动态相互作用.
主要方法:
- 使用时间分辨率单粒子电子冷显微镜 (cryo-EM) 来捕获核糖体内tRNA的快照.
- 冷电磁图像的无偏计算分类使50个不同的中间状态的重建成为可能.
主要成果:
- 详细的3D重建揭示了tRNA在经典,混合和新型中间状态,绘制了它们的轨迹.
- 观察到tRNA运动与核糖体子单元构造变化的结合,特别是小子单元的头部和身体.
- 已表明tRNA和核糖体残留之间的动态相互作用决定了tRNA路径.
结论:
- 核糖体的功能就像一个布朗机器,利用热能来引导tRNA运动.
- 在生理温度下观察到一个令人惊的平坦的能量景观,用于形状变化.
- 这项工作为tRNA转位的机制提供了动态信息和见解.
相关概念视频
Ribosome Profiling
4.3K
Ribosome profiling or ribo-sequencing is a deep sequencing technique that produces a snapshot of active translation in a cell. It selectively sequences the mRNAs protected by ribosomes to get an insight into a cell’s translation landscape at any given point in time.
Applications of ribosome profiling
Ribosome profiling has many applications, including in vivo monitoring of translation inside a particular organ or tissue type and quantifying new protein synthesis levels.
The technique...
Applications of ribosome profiling
Ribosome profiling has many applications, including in vivo monitoring of translation inside a particular organ or tissue type and quantifying new protein synthesis levels.
The technique...
4.3K
Protein Dynamics in Living Cells
2.8K
Different fluorescence-based techniques are used to study the protein dynamics in living cells. These techniques include FRAP, FRET, and PET.
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
2.8K
Ribosomal RNA Synthesis
15.1K
Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
15.1K
Ribosomal RNA Synthesis
4.7K
No description available
4.7K
Improving Translational Accuracy
15.4K
Base complementarity between the three base pairs of mRNA codon and the tRNA anticodon is not a failsafe mechanism. Inaccuracies can range from a single mismatch to no correct base pairing at all. The free energy difference between the correct and nearly correct base pairs can be as small as 3 kcal/ mol. With complementarity being the only proofreading step, the estimated error frequency would be one wrong amino acid in every 100 amino acids incorporated. However, error frequencies observed in...
15.4K
Termination of Translation
28.5K
The large ribosomal subunit has several important structures essential to translation. These include the peptidyl transferase center (PTC) - which is the site where the peptide bond is formed - and a large, internal, water-filled tube through which the nascent polypeptide moves. This latter structure is called the Peptide Exit Tunnel, and it begins at the PTC and spans the body of the large ribosomal subunit. During translation, as the nascent polypeptide chain is synthesized, it passes through...
28.5K


