Analysis of functional structure of ribosomal RNA

本研究旨在通过对核糖体和核糖体RNA（rRNA）功能结构的分析，阐明翻译系统构成和功能的基本原理。翻译系统是生命最基本的系统，阐明其组成原理将有助于阐明生命的起源，本研究首先尝试用吡啶处理去蛋白核糖体，阐明翻译反应的各个步骤，以阐明E. coli核糖体和rRNA。原来，这种核糖体具有非酶（自发）移位活性，但近两年来，核糖体晶体的X射线分析得到了极大的改进，通过原子水平上的三维结构观察，可以阐明核糖体的反应机理。因此，我们将研究目标从E.大肠杆菌到动物线粒体肋 ...更多信息 osomes，因为线粒体核糖体的rRNA缩短了一半，而蛋白质却加倍增大，而分子量和整体大小与E.在牛线粒体核糖体（mitoribosome）的70种蛋白质中，我们已经鉴定出了55种核糖体蛋白质。我们正在研究这些蛋白质。结果表明，只有L7/L12蛋白被E. coli对应物可以与一组线粒体tRNA和翻译因子或一组E. colitRNA和翻译因子，表明大肠杆菌和大肠杆菌之间的核糖体大部分功能是等同的。大肠杆菌和线粒体核糖体，尽管RNA-蛋白质比例是颠倒的。我们也在研究E.大肠杆菌和线粒体核糖体。少

This research project aims to elucidate the basal principle by which the translation system is constituted and functions, by analyzings the, functional structures of the ribosome and ribosomal RNA (rRNA). Since the translation system is the most basic system in life, elucidation of its constitution principle would lead to elucidation of origin of life.In the beginning of this research, we tried to elucidate each step in the translation reaction using protein-deprived ribosomes treated with pyridine for the, purpose of elucidating the functional structure of E. coli ribosomes and rRNA. It turned out that such ribosomes possess non-enzymatic (spontaneous) translocation activity.However, in these two years X-ray analysis of ribosome crystals has been greatly improved and it became possible to elucidate the reaction mechanism of ribosomes by inspection of the three-dimensional structure of ribosomes at atomic level. We thus moved our research target from E. coli to animal mitochondrial rib … More osomes, because mitochondrial ribosomes possess about a half-shortened rRNA and instead, doubly enlarged proteins, while the molecular weight and whole size being similar, as compared to those of E. coli ribosomes, suggesting that the identification of functional sites in rRNA is much easier and moreover, the roles of RNA could have transferred to proteins during evolution of mitochondria.We have already identified 55 ribosomal proteins out of about 70 proteins in bovine, mitochondrial ribosome (mitoribosome) by separating each ribosomal, protein, on the two-dimensional gel electrophoresis followed by its identification by LC/MS technique. We are now characterizing these proteins. It also turned out that a hybrid-type mitoribosome in which only L7/L12 protein was replaced by the E. coli counterpart can function either with a set of mitochondrial tRNA and translation factors or with a set of E. coli tRNA and translation factors, suggesting that the most part of the ribosome is functionally equivalent between E. coli and mitochondrial ribosomes, notwithstanding that the RNA-protein ratio is reversed. We are also examining the origin of this functional interchangeability between E. coli and mitochondrial ribosomes. Less