Kaushal Prem S, Sharma Manjuli R, Agrawal Rajendra K
Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12201-0509, USA.
Division of Translational Medicine, Wadsworth Center, New York State Department of Health, Albany, NY 12201-0509, USA; Department of Biomedical Sciences, School of Public Health, State University of New York at Albany, Albany, NY, USA.
Biochimie. 2015 Jul;114:119-26. doi: 10.1016/j.biochi.2015.03.013. Epub 2015 Mar 20.
Mitochondria carry their own genetic material and gene-expression machinery, including ribosomes, which are responsible for synthesizing polypeptides that form essential components of the complexes involved in oxidative phosphorylation (or ATP generation) for the eukaryotic cell. Mitochondrial ribosomes (mitoribosomes) are quite divergent from cytoplasmic ribosomes in both composition and structure even as their main functional cores, such as the mRNA decoding and peptidyl transferase sites, are highly conserved. Remarkable progress has been made recently towards understanding the structure of mitoribosomes, by obtaining high-resolution cryo-electron microscopic (cryo-EM) maps. These studies confirm previous structural findings that had revealed that a significant reduction in size of ribosomal RNAs has caused topological changes in some of the functionally relevant regions, including the transfer RNA (tRNA)-binding sites and the nascent polypeptide-exit tunnel, within the structure of the mammalian mitoribosome. In addition, these studies provide unprecedented detailed views of the molecular architecture of those regions. In this review, we summarize the current state of knowledge of the structure of the mammalian mitoribosome and describe the molecular environment of its tRNA-exit region.
线粒体携带自身的遗传物质和基因表达机制，包括核糖体，后者负责合成多肽，这些多肽构成了真核细胞中参与氧化磷酸化（或ATP生成）的复合物的重要组成部分。线粒体核糖体（线粒体核糖体）在组成和结构上与细胞质核糖体有很大差异，尽管它们的主要功能核心，如mRNA解码和肽基转移酶位点，高度保守。最近，通过获得高分辨率冷冻电子显微镜（cryo-EM）图谱，在理解线粒体核糖体结构方面取得了显著进展。这些研究证实了先前的结构发现，即核糖体RNA大小的显著减小导致了哺乳动物线粒体核糖体结构中一些功能相关区域的拓扑变化，包括转运RNA（tRNA）结合位点和新生多肽出口通道。此外，这些研究提供了这些区域分子结构前所未有的详细视图。在这篇综述中，我们总结了哺乳动物线粒体核糖体结构的当前知识状态，并描述了其tRNA出口区域的分子环境。
