Quality Control of Protein Translation

蛋白质翻译的质量控制

基本信息

批准号：
6870237
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
项目类别：
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/6870237
关键词：
Escherichia coli RNA binding protein bacterial RNA bacterial genetics bacterial proteins genetic translation protein biosynthesis protein structure function structural biology

项目摘要

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：（由申请人提供）：细菌拥有独特的系统拯救异常停滞的核糖体并标记其降解连接的、部分合成的蛋白质片段。这个质量控制体系，也称为翻译，由非凡的 RNA (SsrA RNA) 精心策划作为 tRNA 来检测和恢复停滞的核糖体，并作为 mRNA 以便于在 C 末端添加短降解标签新生多肽。 SsrA 的所有已知活动都需要 SmpB，这是一种小型的特异性结合 SsrA 且具有高亲和力的蛋白质，可促进其与停滞核糖体的关联。形成的分子基础 SmpB SsrA 复合物以及随后对受损核糖体的识别是不太理解。该研究计划的目标是使用分子遗传学、蛋白质生物化学、生物信息学的结合阐明 SmpB-SsrA 质量机制的结构方法控制系统。重点是 SmpB 如何进行分子表征识别 SsrA RNA 并促进停滞核糖体的检测和拯救。主要是，通过这些研究，我们希望了解生化和 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、哪些碱基特异性进行了接触，以及哪些结构特征有助于形成 SmpB SsrA 复合物及其与核糖体的相互作用。此外，我们希望识别和表征任何可能的其他细胞因素参与这个过程。 RNA 和蛋白质的特定复合物执行许多重要的生物学功能功能，包括RNA加工、RNA周转、RNA运输、RNA折叠、以及将遗传信息从 mRNA 翻译成蛋白质序列。控制 RNA-蛋白质相互作用的原则不充分理解很大程度上是由于缺乏结构信息 RNA-蛋白质复合物。这些原则对于理解很重要 RNA-蛋白质机器，例如核糖体，以及RNA-蛋白质结构和功能一般。 SmpB-SsrA 相互作用相对简单，复合物的稳定性，以及在过程中招募额外的新因子翻译使其成为研究基本原理的理想系统 RNA-蛋白质复合物组装的基础。的理解该系统中的RNA-蛋白质组装过程可能会提供新的见解可推广到 RNA 结合蛋白的分子机制功能。而且，由于SmpB SsrA质量控制体系仅存在于原核生物并涉及新的RNA和蛋白质因子，这些因子对于原核生物来说是必需的大多数（如果不是全部）致病菌的存活，更好地了解这种独特的过程可能允许设计高度具体的新产品抗菌剂。