Substrate Divergence in Aminoacyl-tRNA Biosynthesis

氨酰基-tRNA 生物合成中的底物差异

• 批准号: 7725512
• 负责人: TAMARA L HENDRICKSON
• 金额: --
• 依托单位: WAYNE STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7725512
• 关键词: Address; Amino Acids; Amino Acyl-tRNA Synthetases; Aminoacyl-tRNA Biosynthesis Pathway; Aminoacylation; Anabolism; Anti-Bacterial Agents; Archaea; Asparagine-Specific tRNA; Asparagine-tRNA ligase; Aspartate-tRNA Ligase; Aspartic Acid-Specific tRNA; Bacteria; Bacterial Genome; Categories; Complex; Condition; Cytoplasm; Discrimination; Enzymes; Escherichia coli; Eukaryota; Eukaryotic Cell; Evolution; Foundations; Genes; Genetic Code; Genome; Genomics; Glutamate-tRNA Ligase; Glutamic Acid-Specific tRNA; Glutamine; Glutamine-Specific tRNA; Glutamine-tRNA ligase; Goals; Helicobacter pylori; Human; In Vitro; LGLA; Ligase; Maps; Molecular; Organism; Pathogenicity; Pattern; Prokaryotic Cells; Proteins; Pylorus; Research Personnel; Role; Running; Saccharomyces cerevisiae; Specificity; Testing; Transfer RNA; Transfer RNA Aminoacylation; Translations; Variant; Work; aspartic acid-tRNA; fascinate; fitness; glutamic acid-tRNA; glutamine-tRNA; glutamyl-tRNA(Gln); improved; in vivo; insight; interest; mutant; novel; pathogen; pathogenic bacteria; programs; repair enzyme; repaired; research study

DESCRIPTION (provided by applicant): Aminoacyl-tRNA biosynthesis is fundamental to accurate translation of the genetic code. Not all aminoacyl-tRNA synthetases (the enzymes that biosynthesize the aminoacyl-tRNAs) exist in all organisms, raising important questions about accuracy in translation and evolution of the genetic code. This proposal focuses on glutaminyl-tRNA(Gln) biosynthesis in the human pathogenic bacterium Helicobacter pylori. H. pylori is missing the genes encoding glutaminyl- and asparaginyl-tRNA synthetases (GlnRS and AsnRS, respectively). Consequently, Gln-tRNA(Gln) and Asn-tRNA(Asn) are biosynthesized via misacylated tRNA intermediates [Glu-tRNA(Glu) and Asp-tRNA(Asn), respectively]. These AA-tRNAs are amidatively repaired by a Gin-dependent amidotransferase, Glu-Adt. The H. pylori genome also encodes two glutamyltRNA synthetase (GluRSl and GluRS2). GluRS2 is particularly interesting because it has lost the ability to aminoacylate its "cognate" tRNA(Glu) substrates and only biosynthesizes Glu-tRNA(Gln). The importance of accurate tRNA aminoacylation is absolute to bacterial viability and yet it is clear that different bacteria (H. pylori in particular) have adapted to use divergent tRNA aminoacylation mechanisms. How these different mechanisms contribute to bacterial fitness remains unclear. The major theme of this proposal is to characterize and test the accuracy mechanisms used by H. pylori in vitro and in vivo. These experiments will provide insight into bacterial adaptation and divergence in protein translation. The proposal is divided into three aims. The first will characterize the molecular mechanisms behind the unique tRNA specificity of GluRS2. The second will examine direct versus indirect tRNA aminoacylation in vivo in both H. pylori and in E. coli. The third aim will examine the tRNA selectivity of Glu-Adt, to begin to elucidate the mechanisms by which this enzyme selects its two distinct AA-tRNA substrates.

描述（由申请人提供）： 氨基酰基-TRNA生物合成对于准确翻译遗传密码是基础的。并非所有氨基酰基-TRNA合成酶（生物合成的酶氨基酰基trnas的酶）都存在于所有生物体中，从而提出了有关遗传密码翻译和进化的准确性的重要问题。该提案的重点是人类致病细菌幽门螺杆菌中的谷氨酰胺基-TRNA（GLN）生物合成。幽门螺杆菌缺少编码谷氨酰胺基和天冬酰胺-TRNA合成酶（分别为GLNR和ASNR）的基因。因此，分别通过降低的tRNA中间体[GLU-TRNA（GLU）和ASP-TRNA（ASN）（ASN）生物合成GLN-tRNA（GLN）和ASN-TRNA（ASN）。这些AA-TRNA通过杜松子转移酶Glu-Adt进行了综合修复。幽门螺杆菌基因组还编码两个谷氨酸合成酶（Glursl和Glurs2）。 Glurs2特别有趣，因为它失去了氨基酰基“同源” tRNA（GLU）底物的能力，并且仅生物合成Glu-tRNA（GLN）。 准确的tRNA氨基酰化的重要性绝对对细菌生存能力，但很明显，不同的细菌（尤其是幽门螺杆菌）适应使用不同的tRNA氨基酰化机制。这些不同的机制如何导致细菌适应性尚不清楚。该提案的主要主题是表征和测试幽门螺杆菌在体外和体内使用的准确性机制。这些实验将洞悉蛋白质翻译中细菌适应性和差异。该提议分为三个目标。第一个将表征Glurs2独特的tRNA特异性背后的分子机制。第二个将检查幽门螺杆菌和大肠杆菌中的体内直接与间接tRNA氨基酰化。第三个目标将检查GLU-ADT的tRNA选择性，以开始阐明该酶选择其两种不同的AA-TRNA底物的机制。