Mechanism of Protein Synthesis in Mammalian Mitochondria

哺乳动物线粒体蛋白质合成机制

• 批准号: 6635896
• 负责人: LINDA L SPREMULLI
• 金额: $ 27.73万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 1984
• 资助国家: 美国
• 起止时间: 1984-05-01 至 2005-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6635896
• 关键词: X ray crystallography; aminoacid tRNA ligase; aminoacyl tRNA; cell component structure /function; chemical association; chemical kinetics; fluorescent dye /probe; genetic regulation; genetic translation; guanine nucleotides; intermolecular interaction; mass spectrometry; messenger RNA; methionine; mitochondria; model design /development; molecular assembly /self assembly; molecular site; physical model; protein biosynthesis; protein structure function; ribosomal proteins; ribosomes; site directed mutagenesis; structural biology; translation factor

DESCRIPTION (provided by applicant): The generation.of energy in mammalian mitochondria is accomplished by a series of oligomeric complexes in the inner membrane. The synthesis and assembly of these complexes requires genetic information contained in both the nuclear and mitochondrial genomes. Limited information is available on the mechanism by which the mitochondrially-encoded components in these complexes are synthesized. The overall objective of this research is to investigate the mechanism of protein biosynthesis in mammalian mitochondria. The first objective of is focused on polypeptide chain initiation and contains three parts: (1) An examination of the properties and mechanism of action of the factor (initiation factor 2, IF-2mt) which promotes the binding of the initiator tRNA to the ribosome. We will examine the domain organization of IF-2mt, its interaction with the mitochondrial ribosome and its ability to use the unusual tRNAMet in mitochondria that must serve both as the initiator and as an elongator tRNA. (2) Properties and mechanism of action of a newly discovered mammalian mitochondrial initiation factor distantly related to prokaryotic initiation factor 3. The properties of this factor including its domain organization, interaction with mitochondrial ribosomes and its role in proofreading the AUG and AUA codons used for methionine in mammalian mitochondria will be examined. (3) Investigation into the role of additional factors in the formation of the initiation complex in mitochondria. The second major objective of this application focuses on the properties of the translation elongation factor (EF-Tumt) that promotes the binding of aminoacyl-tRNA to the A-site of the ribosome. A collaborative project has been established with the laboratory of Dr. Jens Nyborg (Univ. Aarhus, Denmark) to determine the structures of the ternary complex (EF-Tumt.GTP.aa-tRNA), of the complex formed between EF-Tumt and its guanine nucleotide exchange factor EF-Tsmt and of the active (GTP-form) of EF-Tumt. EF-Tumt is able to promote the binding of the structurally unusual mitochondrial aa-tRNAs to the A-site of the ribosome. The regions of EF-Tumt that allow it to use mitochondrial aa-tRNAs will be examined using site-directed mutagenesis.

描述（由申请人提供）：哺乳动物能量的产生 线粒体是由内部的一系列寡聚复合物完成的 膜。这些复合物的合成和组装需要遗传 核基因组和线粒体基因组中包含的信息。有限的 有关线粒体编码的机制的信息是可用的 合成这些复合物中的成分。本次活动的总体目标 研究目的是探讨哺乳动物蛋白质生物合成的机制 线粒体。第一个目标集中于多肽链起始 包括三个部分： (1) 性质和机制的考察 促进结合的因子（起始因子 2，IF-2mt）的作用 起始子 tRNA 到核糖体。我们将检查域组织 IF-2mt 的作用、其与线粒体核糖体的相互作用及其能力 在线粒体中使用不寻常的 tRNAMet，它必须同时充当引发剂 以及作为延伸子 tRNA。 (2)新药的性质和作用机制 发现哺乳动物线粒体起始因子与 原核起始因子 3。该因子的特性，包括其 结构域组织、与线粒体核糖体的相互作用及其在 校对哺乳动物蛋氨酸的 AUG 和 AUA 密码子 将检查线粒体。 (3) 附加作用的调查 线粒体起始复合物形成的因素。第二个 该应用程序的主要目标集中于 翻译延伸因子 (EF-Tumt) 促进结合 氨酰基-tRNA 连接到核糖体的 A 位点。一个合作项目已经 与 Jens Nyborg 博士（丹麦奥胡斯大学）的实验室建立 确定三元复合物 (EF-Tumt.GTP.aa-tRNA) 的结构 EF-Tumt 与其鸟嘌呤核苷酸交换因子形成复合物 EF-Tsmt 和 EF-Tumt 的活性（GTP 形式）。 EF-Tumt 能够促进 结构异常的线粒体 aa-tRNA 与 A 位点的结合 核糖体。允许 EF-Tumt 使用线粒体 aa-tRNA 的区域 将使用定点诱变进行检查。