Evolution of a protein-rich mitochondrial ribosome: implications for human genetic disease
Evolution of a protein-rich mitochondrial ribosome: implications for human genetic disease
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DOI：
10.1016/s0378-1119(01)00808-3
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发表时间：
2002-03-06
期刊：
影响因子：
3.5
通讯作者：
O'Brien, TW
中科院分区：
文献类型：
--
作者：
O'Brien, TW
线粒体核糖体包含已知最多样化的核糖体群。哺乳动物线粒体核糖体 (55S) 与细菌 (70S) 和细胞质核糖体 (80S) 以及其他种类的线粒体核糖体出乎意料地不同。牛线粒体核糖体已被开发为研究人类线粒体核糖体的模型系统，以解决与这些有趣的核糖体的结构、功能、生物合成和进化相关的几个问题。来自每个亚基的牛线粒体核糖体蛋白 (MRP) 已在个体和电泳特性、氨基酸序列、拓扑分布、RNA 结合特性、进化关系以及与核糖体功能域亲和探针的反应方面得到鉴定和表征。这些核糖体的几个独特特性正在被阐明，包括它们的抗生素敏感性和组成。哺乳动物线粒体核糖体缺乏细菌核糖体的几种主要RNA干结构，但它们含有相应较高的蛋白质含量（多达80种蛋白质），这表明在这些核糖体的进化过程中蛋白质取代了RNA结构元件。尽管它们的 RNA 含量较低，但由于它们含有“额外”蛋白质，它们的物理尺寸比细菌核糖体大。线粒体核糖体中的额外蛋白质是“新的”，因为它们与细菌或细胞质核糖体中的蛋白质不同源。一些新蛋白质似乎具有双功能。所有哺乳动物 MRP 均在核基因（与编码细胞质核糖体蛋白的基因组不同）中编码，这些基因比编码细胞质核糖体蛋白的基因进化得更快。 MRP 被导入线粒体，在那里它们与线粒体转录的 rRNA 协调组装成核糖体，核糖体负责将 13 种 mRNA 翻译为氧化磷酸化系统的必需蛋白质。人们对人类 MRP 基因的结构、组织、染色体位置和表达越来越感兴趣。线粒体核糖体功能所必需的蛋白质是参与人类遗传疾病的候选蛋白质。 (C) 2002 Elsevier Science B.V. 保留所有权利。
Mitochondrial ribosomes comprise the most diverse group of ribosomes known. The mammalian mitochondrial ribosomes (55S) differ unexpectedly from bacterial (70S) and cytoplasmic ribosomes (80S), as well as other kinds of mitochondrial ribosomes. The bovine mitochondria ribosome has been developed as a model system for the study of human mitochondria ribosomes to address several questions related to the structure, function, biosynthesis and evolution of these interesting ribosomes. Bovine mitochondria ribosomal proteins (MRPs) from each subunit have been identified and characterized with respect to individuality and electrophoretic properties, amino acid sequence, topographic disposition, RNA binding properties, evolutionary relationships and reaction with affinity probes of ribosomal functional domains. Several distinctive properties of these ribosomes are being elucidated, including their antibiotic susceptibility and composition. Mammalian mitochondria ribosomes lack several of the major RNA stem structures of bacterial ribosomes but they contain a correspondingly higher protein content (as many as 80 proteins), suggesting a model where proteins have replaced RNA structural elements during the evolution of these ribosomes. Despite their lower RNA content they are physically larger than bacterial ribosomes, because of the 'extra' proteins they contain. The extra proteins in mitochondria ribosomes are 'new' in the sense that they are not homologous to proteins in bacterial or cytoplasmic ribosomes. Some of the new proteins appear to be bifunctional. All of the mammalian MRPs are encoded in nuclear genes (a separate set from those encoding cytoplasmic ribosomal proteins) which are evolving more rapidly than those encoding cytoplasmic ribosomal proteins. The MRPs are imported into mitochondria where they assemble coordinately with mitochondrially transcribed rRNAs into ribosomes that are responsible for translating the 13 mRNAs for essential proteins of the oxidative phosphorylation system. Interest is growing in the structure, organization, chromosomal location and expression of genes for human MRPs. Proteins which are essential for mitoribosome function are candidates for involvement in human genetic disease. (C) 2002 Elsevier Science B.V. All rights reserved.