Quality Control of Protein Translation

蛋白质翻译的质量控制

• 批准号: 6721207
• 负责人: A. WALI KARZAI
• 金额: $ 25.89万
• 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 2007-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6721207
• 关键词: Escherichia coli; RNA binding protein; bacterial RNA; bacterial genetics; bacterial proteins; genetic translation; protein biosynthesis; protein structure function; structural biology

DESCRIPTION: (provided by applicant): Bacteria possess a unique system for rescuing aberrantly stalled ribosomes and marking for degradation the still linked, partially synthesized protein fragments. This quality control system, also known as transtranslation, is orchestrated by a remarkable RNA (SsrA RNA) that functions as a tRNA to detect and revive stalled ribosomes and as an mRNA to facilitate the addition of a short degradation tag to the C-terminus of nascent polypeptides. All known activities of SsrA require SmpB, a small protein that binds SsrA specifically and with high affinity to promote its association with stalled ribosomes. The molecular basis for the formation of the SmpB SsrA complex and the subsequent recognition of impaired 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 the SmpB-SsrA quality control system. The emphasis is on the molecular characterization of how SmpB recognizes SsrA RNA and promotes the detection and rescue of stalled ribosomes. Principally, through these studies we wish to understand the biochemical and structural basis for the interactions of SmpB with SsrA RNA. Specifically we want to learn what amino acid residues are involved, what base-specific contacts are made, and what structural features contribute to the formation of the SmpB SsrA complex and its interaction with the ribosome. Furthermore, we wish to identify and characterize any additional cellular factors that might participate in this process. Specific complexes of RNA and protein perform many essential biological functions, including RNA processing, RNA turnover, RNA transport, RNA folding, as well as the translation of genetic information from mRNA into protein sequences. Principles that govern RNA-protein interactions are inadequately understood due in large part to a paucity of structural information on RNA-protein complexes. These principles are important for understanding RNA-protein machines, such as the ribosome, and RNA-protein structure and function in general. The relative simplicity of the SmpB-SsrA interaction, the stability of the complex, and recruitment of additional novel factors during trans-translation makes it an ideal system to study the basic principles underlying the assembly of RNA-protein complexes. Understanding of the RNA-protein assembly processes in this system are likely to provide new insights generalizable to the molecular mechanism of how RNA-binding proteins function. Moreover, because the SmpB SsrA quality control system exists only in prokaryotes and involves novel RNA and protein factors that are essential for the survival of most (if not all) pathogenic bacteria, a better understanding of this unique process might allow the design of highly specific new anti-bacterial agents.

描述：(申请人提供)：细菌拥有一种独特的系统 挽救异常停滞的核糖体并标记蒸馏器的退化 连接的、部分合成的蛋白质片段。这个质量控制体系， 也被称为翻译，是由一种非凡的RNA(SsrA RNA)编排的 其功能是作为tRNA来检测和恢复停滞的核糖体，以及作为一种信使核糖核酸 为了便于在C端增加一个短的降解标签 新生多肽。所有已知的SsrA活动都需要SmpB，一个小的 与SsrA特异结合并具有高亲和力的蛋白质，促进其 与停滞的核糖体相关。它的形成的分子基础 SmpB SsrA复合体和随后对受损核糖体的识别是 不是很清楚。该研究计划的目标是使用一种 分子遗传学、蛋白质生物化学、生物信息学和 用结构方法阐明SmpB-SsrA质量的机制 控制系统。重点是SmpB如何的分子表征 识别SsrA RNA，促进检测和挽救停滞的核糖体。 主要是通过这些研究，我们希望了解生物化学和 SmpB与SsrA RNA相互作用的结构基础。具体来说，我们 想要了解涉及哪些氨基酸残基，哪些特定的碱基？ 进行了接触，以及什么结构特征有助于形成 SmpB SsrA复合体及其与核糖体的相互作用。此外，我们 希望确定和表征任何其他细胞因子可能 参与这一进程。 RNA和蛋白质的特定复合体执行许多基本的生物功能 功能，包括RNA加工，RNA周转，RNA转运，RNA折叠， 以及将基因信息从信使核糖核酸转化为蛋白质 序列。管理RNA-蛋白质相互作用的原则是不够的 理解在很大程度上是由于缺乏关于 RNA-蛋白质复合体。这些原则对于理解 RNA-蛋白质机器，如核糖体，以及RNA-蛋白质结构和 功能一般。SmpB-SsrA相互作用的相对简单， 复合体的稳定性，并在期间招募其他新的因子 翻译使其成为研究基本原则的理想体系 在RNA-蛋白质复合体组装的基础上。对这一概念的理解 这个系统中的RNA-蛋白质组装过程可能会提供新的 对RNA结合蛋白的分子机制的认识 功能。此外，由于SmpB SsrA质量控制体系仅存在于 原核生物，涉及新的RNA和蛋白质因子，这些因子对 大多数(如果不是全部)致病菌的生存，更好地了解 这一独特的过程可能允许设计高度具体的新 抗菌剂。