Department of Chemistry, University of California, Berkeley, Berkeley, United States.
Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, United States.
Elife. 2020 Sep 14;9:e60482. doi: 10.7554/eLife.60482.
Using cryo-electron microscopy (cryo-EM), we determined the structure of the 70S ribosome with a global resolution of 2.0 Å. The maps reveal unambiguous positioning of protein and RNA residues, their detailed chemical interactions, and chemical modifications. Notable features include the first examples of isopeptide and thioamide backbone substitutions in ribosomal proteins, the former likely conserved in all domains of life. The maps also reveal extensive solvation of the small (30S) ribosomal subunit, and interactions with A-site and P-site tRNAs, mRNA, and the antibiotic paromomycin. The maps and models of the bacterial ribosome presented here now allow a deeper phylogenetic analysis of ribosomal components including structural conservation to the level of solvation. The high quality of the maps should enable future structural analyses of the chemical basis for translation and aid the development of robust tools for cryo-EM structure modeling and refinement.
使用冷冻电子显微镜（cryo-EM），我们确定了具有 2.0 Å 全局分辨率的 70S 核糖体结构。这些图谱揭示了蛋白质和 RNA 残基的明确定位、它们的详细化学相互作用和化学修饰。值得注意的特征包括核糖体蛋白中首次出现的异肽键和硫代酰胺骨架取代的例子，前者可能在生命的所有领域中都保守。图谱还显示了小（30S）核糖体亚基的广泛溶剂化以及与 A 位和 P 位 tRNA、mRNA 和抗生素巴龙霉素的相互作用。本文呈现的细菌核糖体图谱和模型现在可以更深入地分析核糖体成分的系统发育，包括结构的保守性，达到溶剂化的水平。图谱的高质量应该能够为未来的翻译化学基础的结构分析提供帮助，并有助于开发用于冷冻电子显微镜结构建模和细化的强大工具。
