Institute of Molecular Biology and Biophysics, ETH Zurich, CH-8093 Zurich, Switzerland.
California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, CA 94720, USA; Molecular Biophysics and Integrative Bio-Imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Curr Opin Struct Biol. 2018 Apr;49:44-53. doi: 10.1016/j.sbi.2017.12.009. Epub 2018 Jan 16.
Mitochondrial ribosomes (mitoribosomes) almost exclusively synthesize essential components of the oxidative phosphorylation machinery. Dysfunction of mitochondrial protein biosynthesis leads to human diseases and plays an important role in the altered metabolism of cancer cells. Recent developments in cryo-electron microscopy enabled the structural characterization of complete yeast and mammalian mitoribosomes at near-atomic resolution. Despite originating from ancestral bacterial ribosomes, mitoribosomes have diverged in their composition and architecture. Mitoribosomal proteins are larger and more numerous, forming an extended network around the ribosomal RNA, which is expanded in yeast and highly reduced in mammals. Novel protein elements at the entrance or exit of the mRNA channel imply a different mechanism of mRNA recruitment. The polypeptide tunnel is optimized for the synthesis of hydrophobic proteins and their co-translational membrane insertion.
线粒体核糖体（mitoribosomes）几乎专门合成氧化磷酸化机器的基本组成部分。线粒体蛋白生物合成的功能障碍导致人类疾病，并在癌细胞改变的代谢中发挥重要作用。低温电子显微镜的最新发展使完整的酵母和哺乳动物线粒体核糖体在近原子分辨率下的结构特征得以实现。尽管起源于祖先细菌核糖体，但线粒体核糖体在组成和结构上已经分化。线粒体核糖体蛋白更大且更多，在核糖体 RNA 周围形成扩展的网络，该网络在酵母中扩展，在哺乳动物中高度减少。mRNA 通道入口或出口处的新蛋白元件意味着 mRNA 募集的机制不同。多肽隧道经过优化，可用于合成疏水性蛋白及其共翻译的膜插入。
