Functions of 4.5S RNA in the bacterial cell

4.5S RNA 在细菌细胞中的功能

基本信息

批准号：
7214726
负责人：
James Gregory PHILLIPS
金额：
$ 13.63万
依托单位：
IOWA STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2004
资助国家：
美国
起止时间：
2004-04-01 至 2009-03-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): The signal recognition particle (SRP) is a highly evolutionarily conserved ribonucleoprotein complex that functions to target proteins into biological membranes. Because E. coli contains a "minimal" SRP, consisting of the Ffh protein in association with a 4.5S RNA species, it provides an attractive system to understand how the translocation machinery functions in all living cells. Understanding the role of the RNA component of the bacterial SRP function is complicated by its essentiality for cell growth and its involvement in protein synthesis. Since few studies have been performed to understand how the sequence determinants of 4.5S RNA contribute to its function in vivo, little is known about why the RNA is an essential component of both the membrane protein localization and protein translation machinery. The long-term goal of our research is to determine how 4.5S RNA functions as a component of the SRP to target proteins to the inner membrane, and in translation by its interaction with elongation factor G. We propose to perform a systematic genetic characterization of 4.5S RNA to determine how the structure of this molecule contributes to its activity, and to probe the function of the RNA in both protein synthesis and membrane protein localization. Our lack of knowledge about the cellular roles of 4.5S RNA is significant in that it prevents us from fully describing the essential processes of protein localization and polypeptide synthesis on a molecular level. Due to the high evolutionary conservation of the SRP RNA, with homologues found in all living species examined to date, we will also better comprehend how this RNA species functions in all living systems. Although recent efforts have been placed largely on in vitro analysis of 4.5S RNA, including biochemical characterization and structural determinations, efforts to understand the function of 4.5 S RNA in vivo has lagged in part due to the lack of genetic systems for studying this molecule. These studies should contribute to improved methods to express and localize membrane proteins of medical importance, as well as lead to the identification of antimicrobial agents.

描述（由申请人提供）：信号识别粒子（SRP）是一种高度进化保守的核糖核蛋白复合物，可将蛋白靶向生物膜。因为大肠杆菌包含一个“最小” SRP，由FFH蛋白与4.5S RNA物种结合在一起，因此它提供了一个有吸引力的系统，以了解易位机械如何在所有活细胞中起作用。了解细菌SRP功能的RNA成分的作用是由于其对细胞生长及其参与蛋白质合成的重要性而变得复杂。由于很少进行研究以了解4.5S RNA的序列决定因素如何促进其在体内功能，因此对于为什么RNA是膜蛋白定位和蛋白质翻译机械的重要组成部分，知之甚少。 The long-term goal of our research is to determine how 4.5S RNA functions as a component of the SRP to target proteins to the inner membrane, and in translation by its interaction with elongation factor G. We propose to perform a systematic genetic characterization of 4.5S RNA to determine how the structure of this molecule contributes to its activity, and to probe the function of the RNA in both protein synthesis and membrane protein localization.我们对4.5S RNA的细胞作用的知识不足很大，因为它使我们无法完全描述分子水平上蛋白质定位和多肽合成的基本过程。由于SRP RNA的高进化保护，并且在迄今为止检查的所有生物物种中都发现了同源物，我们还将更好地理解该RNA物种在所有生物系统中的作用。尽管最近的努力主要是在4.5S RNA的体外分析上，包括生化表征和结构确定，但了解体内4.5 S RNA的功能的努力部分滞后于研究该分子的基因系统。这些研究应有助于改善表达和定位医学重要性的膜蛋白的方法，并导致鉴定抗菌剂。