Quality Control of Protein Translation

蛋白质翻译的质量控制

• 批准号: 7630318
• 负责人: A. WALI KARZAI
• 金额: $ 26.2万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-04-01 至 2009-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7630318
• 关键词: Affinity; Alanine-Specific tRNA; Alanine-tRNA Ligase; Amino Acids; Anti-Bacterial Agents; Anticodon; Binding; Biochemical; Bioinformatics; Biological Process; C-terminal; Charge; Complex; Condition; DNA; Data; Depth; Detection; Distal; EEF1A1 gene; Elements; Ensure; Escherichia coli; Event; Exonuclease; Exoribonucleases; Family; Genetic; Goals; Guanosine Triphosphate; Guanosine Triphosphate Phosphohydrolases; Hydrolysis; Kinetics; Laboratories; Life; Light; Link; Measures; Mediating; Membrane Proteins; Messenger RNA; Molecular; Molecular Genetics; Numbers; Object Attachment; Organism; Pathway interactions; Peptide Elongation Factor Tu; Peptides; Physiological; Play; Positioning Attribute; Process; Prokaryotic Cells; Property; Protein Binding; Protein Biochemistry; Protein Fragment; Proteins; Proteolysis; Quality Control; RNA; RNA-Protein Interaction; Rate; Relative (related person); Research; Ribosomes; Role; Site; SmpB protein; Staging; Structure; Surface; System; Tail; Transcript; Transfer RNA; Translations; Variant; Virulence; base; design; fascinate; human EEF1A1 protein; mRNA Decay; mRNA Stability; member; novel; pathogenic bacteria; programs; protein function; quality assurance; ribonuclease R; stem; tmRNA

The accurate flow of genetic information from DNA to RNA to protein is essential for all living organisms. An astonishing array of quality-assurance mechanisms have evolved to ensure that high degree of fidelity is maintained at every stage of this process. One of the most fascinating quality control mechanisms involves tmRNA, also known as SsrA or 10Sa RNA. tmRNA is a versatile and highly conserved bacterial molecule endowed with the combined structural and functional properties of both a tRNA and an mRNA. Our previous studies have shown that all known activities of tmRNA require SmpB, a small protein that binds tmRNA specifically and with high affinity to promote its association with stalled ribosomes. The SmpB-tmRNA system orchestrates three key biological functions: 1) recognition and rescue of ribosomes stalled on aberrant mRNAs, 2) disposal of the causative defective mRNAs, and 3) addition of a degradation tag to the incomplete protein fragments for directed proteolysis. Although not essential in E. coli, tmRNA activity is essential for bacterial survival under adverse conditions and for virulence in some, and perhaps all, pathogenic bacteria. Recent evidence from our laboratory suggests that in addition to its quality control function the tmRNA system might also play a key regulatory role in certain physiological pathways. Moreover, because the SmpB and tmRNA are found only in prokaryotes, involves novel RNA and protein factors, and is essential for the survival of pathogenic bacteria, a deeper mechanistic understanding of this system might allow the design of highly specific new anti-bacterial agents. The molecular basis for the formation of the SmpB-tmRNA complex and the subsequent recognition of stalled ribosomes are not well understood. The objective of this research program is to use a combination of molecular genetics, protein biochemistry, bioinformatics, and structural approaches to elucidate the mechanism of action of the SmpB-tmRNA quality control system. The emphasis is on the molecular characterization of how SmpB-tmRNA complex recognizes stalled ribosomes and promotes the detection and selective decay of the causative defective mRNA by the 3¿-5¿ exonuclease RNase R. Specifically, through these studies we wish to understand the biochemical and structural basis for the interactions of SmpB and RNase R with tmRNA and the ribosome; i.e. what amino acid residues are involved, what base specific contacts are made, what structural features contribute to the formation of the tmRNAassociated SmpB and RNase R complexes and their interaction with stalled ribosome.

遗传信息从DNA到RNA再到蛋白质的准确流动对所有生物都是必不可少的 有机体一系列令人惊讶的质量保证机制已经发展起来，以确保 在该过程的每个阶段都保持高度的保真度。一个最迷人的 质量控制机制涉及tmRNA，也称为SsrA或10 Sa RNA。tmRNA是一种 多功能和高度保守的细菌分子， tRNA和mRNA的功能特性。我们之前的研究表明， 已知的tmRNA活性需要SmpB，一种特异性结合tmRNA的小蛋白， 具有高亲和力以促进其与停滞的核糖体的结合。SmpB-tmRNA系统 协调三个关键的生物功能：1）识别和拯救核糖体停滞在 异常的mRNA，2）处理致病缺陷的mRNA，和3）添加 将降解标签添加到不完整的蛋白质片段上用于定向蛋白水解。尽管未 在E. tmRNA活性是细菌在不利条件下生存所必需的 以及某些甚至所有致病细菌的毒力。我们最近的证据显示， 实验室表明，除了其质量控制功能外，tmRNA系统还可能 在某些生理途径中起着关键的调节作用。此外，由于SmpB和 tmRNA仅在原核生物中发现，涉及新的RNA和蛋白质因子，是必需的 对于致病菌的生存，更深入地了解这个系统的机制， 可能允许设计高度特异性的新抗菌剂。 SmpB-tmRNA复合物形成的分子基础和随后的细胞凋亡的分子基础是： 对停滞核糖体的识别还没有很好的理解。这项研究计划的目的是 是利用分子遗传学、蛋白质生物化学、生物信息学和 阐明SmpB-tmRNA质量控制作用机制的结构方法 系统重点是SmpB-tmRNA复合物的分子特征 识别停滞的核糖体，促进病原体的检测和选择性衰变， 3 <$-5 <$核酸外切酶RNase R导致的mRNA缺陷。通过这些研究，我们希望 了解SmpB和RNase R相互作用的生化和结构基础 与tmRNA和核糖体;即涉及什么氨基酸残基，什么碱基特异性 接触，什么样的结构特征有助于形成的tmRNAassociated SmpB和RNase R复合物及其与停滞核糖体的相互作用。