Quality Control of Protein Translation

蛋白质翻译的质量控制

• 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
• 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

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）：细菌具有独特的系统 营救异常停滞的核糖体并标记以降解仍然 连接的，部分合成的蛋白质片段。这个质量控制系统， 也称为trans骨，由出色的RNA（SSRA RNA）精心策划 它是检测和复兴失速核糖体和mRNA的tRNA 为了促进向C-terminus添加一个简短的降解标签 新生多肽。 SSRA的所有已知活动都需要SMPB，一个小的 特异性结合并具有高亲和力以促进其蛋白质的蛋白质 与停滞的核糖体相关。形成的分子基础 SMPB SSRA综合体和随后对核糖体受损的识别是 不太了解。该研究计划的目的是使用 分子遗传学，蛋白质生物化学，生物信息学和 阐明SMPB-SSRA质量机制的结构方法 控制系统。重点是SMPB的分子表征 识别SSRA RNA，并促进对失速核糖体的检测和营救。 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。特别是我们 想了解涉及哪些氨基酸残基，哪些基碱特异性 建立了联系，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 希望识别并表征可能 参加此过程。 RNA和蛋白质的特定复合物进行许多必不可少的生物学 功能，包括RNA处理，RNA更新，RNA传输，RNA折叠， 以及从mRNA转化为蛋白质的遗传信息的翻译 序列。控制RNA - 蛋白质相互作用的原则不足 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，例如核糖体和RNA蛋白结构，以及 通常功能。 SMPB-SSRA相互作用的相对简单性， 复合物的稳定性，以及在 跨翻译使其成为研究基本原理的理想系统 RNA-蛋白质复合物的组装。理解 该系统中的RNA蛋白质组装过程可能会提供新的 可以推广到RNA结合蛋白的分子机制的洞察力 功能。此外，因为SMPB SSRA质量控制系统仅存在于 原核生物，涉及新颖的RNA和蛋白质因子，这些因素对于 大多数（如果不是全部）病原细菌的生存，更好地理解 在这个独特的过程中，可以设计高度特定的新 抗菌剂。