STRUCTURAL BASIS OF RNA-CATALYZED AMINOACYLATION OF RNA

RNA 催化氨基酰化的结构基础

• 批准号: 6800516
• 负责人: JOHN G ARNEZ
• 金额: $ 23.67万
• 依托单位: UNIVERSITY OF LOUISVILLE
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-09-15 至 2008-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6800516
• 关键词: RNA; X ray crystallography; active sites; acylation; aminoacid; apoenzymes; electrospray ionization mass spectrometry; enzyme mechanism; gel electrophoresis; nuclear magnetic resonance spectroscopy; nucleotides; protein biosynthesis; ribosomes; ribozymes; structural biology

DESCRIPTION (provided by applicant): Attachment of amino acids to adapter RNA molecules is a key reaction in protein biosynthesis. The aminoacylation reaction is catalyzed in the cell by aminoacyl-tRNA synthetases. Recently, three classes of catalytic RNAs (ribozymes) that recapitulate this activity by transferring the aminoacyl moiety from a pre-formed adenylate to their own 3'-termini have been obtained through in vitro selection. The first class contains RNAs that accept any aminoacyl moiety, whereas members of the second class are specific for phenylalanine and tyrosine. Ribozymes of the third class also catalyze the formation of dipeptides, a reaction analogous to that catalyzed by a large ribozyme, the ribosome. In this proposal, the three-dimensional structures of self-aminoacylating RNAs of the three classes will be determined by x-ray crystallography. The ribozymes will be analyzed in complex with substrate and product analogs. The structural information obtained in this study will reveal the configuration of the active site of these ribozymes, organization of the amino acid-specific binding pocket and the mechanism of catalysis. It will help clarify the issue of whether the aminoacyl transfer to a peptide or an RNA involves entropic catalysis (i.e., precise positioning of the substrates) or it requires special catalytic groups on the enzyme, such as an acid or base; hence, it will add to our understanding of the reactions catalyzed by the larger biological systems such as the aminoacyl-tRNA synthetases and the ribosome.

描述（由申请人提供）：氨基酸与适配RNA分子的附着是蛋白质生物合成中的关键反应。氨酰化反应在细胞内由氨酰- trna合成酶催化。最近，通过体外筛选获得了三种催化rna（核酶），它们通过将氨基酸基片段从预形成的腺苷酸转移到它们自己的3'端来重现这种活性。第一类rna可以接受任何氨基酰基片段，而第二类rna只接受苯丙氨酸和酪氨酸。第三类核酶也催化二肽的形成，这一反应类似于大型核酶核糖体所催化的反应。在这一提议中，这三类自胺酰化rna的三维结构将通过x射线晶体学来确定。核酶将与底物和产物类似物进行复合体分析。本研究获得的结构信息将揭示这些核酶活性位点的构型、氨基酸特异性结合袋的组织结构和催化机制。这将有助于澄清氨基酰基转移到肽或RNA是否涉及熵催化（即，底物的精确定位）或它需要酶上的特殊催化基团，如酸或碱的问题；因此，它将增加我们对更大的生物系统如氨基酰基trna合成酶和核糖体催化的反应的理解。