MAMMALIAN AMINOACYL-TRNA SYNTHETASE COMPLEX

拟议研究的目的是阐明 哺乳动物的结构-功能关系及其调控 氨酰-tRNA合成酶。除了氨基酰化同源tRNAs 对于蛋白质的生物合成，哺乳动物合成酶参与 细胞内蛋白分解，合成信号核苷酸(AppppA 和类似物)氨基酸运输、自身免疫性疾病和衰老。 哺乳动物中至少有八种氨基酰-tRNA合成酶 以多酶复合体的形式存在。合成酶复合体 呈现了一种独特而有趣的生化排列 既有结构，又有监管。这项研究项目提出 在更高的层次上描绘基本原则 蛋白质的结构组织和进化的功能 这样的蛋白质结构。建议项目的具体目标 1)克隆哺乳动物氨基酰tRNA并测序 合成酶，并获得这些合成酶的高水平表达 哺乳动物细胞中的合成酶；2)测定氨基酸 与合成酶复合体组装有关的序列，以及 目的：在体内研究合成酶复合体在血管紧张素转换酶中的作用。 合成酶周转与信号核苷酸生物合成；3) 氨基酰基-tRNA合成酶与蛋白质相互作用的体外研究 合成酶复合体，并分析其在合成中的作用 信号核苷酸与哺乳动物蛋白质生物合成；4)至 克隆和定位氨基酰-tRNA合成酶基因，以及 确定基因的剪接位点和调控序列 上游侧翼区域。将使用的方法如下 酶学的、结构的和遗传的。考虑到核心作用 所有细胞功能中的蛋白质，对结构的理解， 蛋白质中这些关键酶的功能及其调控 生物合成是非常重要的。

The objective of the proposed research is to elucidate the structure-function relationship and the regulation of mammalian aminoacyl-tRNA synthetases. Besides aminoacylating cognate tRNAs for protein biosynthesis, mammalian synthetases participate in intracellular proteolysis, synthesis of signal nucleotides (AppppA and analogs) amino acid transport, autoimmune diseases and aging. At least eight of the mammalian aminoacyl-tRNA synthetases associate as a multi-enzyme complex. The synthetase complex presents a unique and interesting biochemical arrangement in terms of both structure and regulation. This research project proposes to delineate the fundamental principles in the high order of structural organization of proteins, and the evolved functions of such protein structure. The specific aims of the proposed projects are: 1) to clone and sequence mammalian aminoacyl-tRNA synthetases, and to obtain high level of expression of these synthetases in mammalian cells; 2) to determine the amino acid sequences involved in the assembly of the synthetase complex, and to study in vivo the roles of the synthetase complex in the synthetase turnover and the signal nucleotide biosynthesis; 3) to study in vitro the interaction of aminoacyl-tRNA synthetases with the synthetase complex, and to analyze its roles in the synthesis of signal nucleotide and mammalian protein biosynthesis; 4) to clone and map the genes of aminoacyl-tRNA synthetases, and determine the splicing sites and the regulatory sequences in the upstream flanking region. The methods to be used will be enzymological, structural and genetic. In view of the central role of proteins in all cell functions, understanding of the structure, function and the regulation of these essential enzymes in protein biosynthesis is of great importance.