Structural dynamics of peptide-translocating ABC transporters

肽转位 ABC 转运蛋白的结构动力学

基本信息

批准号：
10580376
负责人：
Hassane S Mchaourab
金额：
$ 2.87万
依托单位：
VANDERBILT UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-08-21 至 2024-07-31
项目状态：
已结题

项目摘要

Protein export across membranes is a critical process for life. In prokaryotes, multiple protein transport systems were evolved to facilitate the transfer of amphipathic and hydrophilic proteins of impressive sizes across lipid hydrophobic barriers. The simplest of these systems consist of an ATP binding Cassette (ABC) transporter which harnesses the energy of ATP hydrolysis to power the movement of cargo peptides or proteins across the cell membranes. In gram positive bacteria, ABC transporters export antimicrobial or quorum sensing peptides which serve to endow the organism with survival advantages under conditions of limited resources. The long term goal of this application is to illuminate the conformational dynamics of peptidase-containing ABC transporters (PCATs) which utilizes a built in cysteine protease domain to cleave the signal sequence of the cargo peptide prior to export. The premise of our strategy is grounded in 1) recent high resolution structures of PCATs that define their molecular architecture and set the stage for detailed investigation of the mechanism by which these transporters enable protein translocation and 2) the track record of the PI in the application of state of the art electron paramagnetic resonance (EPR) spectroscopy in conjunction with mutagenic analysis to active transporters. The specific aims are designed to address unanswered questions in the field including the structural basis of alternating access powered by ATP turnover, the determinants of cargo protein specificity, and the structure and environment of the cargo protein as it transitions through the transporter. Over the last decade, our approach integrated with molecular modeling has been instrumental in revealing the structural dynamics of multidrug ABC exporters and providing insight into the mechanistic diversity within this family. The significance of the proposed research stems from a molecular target at the junction of antibacterial peptide transport, bacterial immunity and represents a fundamental biochemical process by which proteins are exported across lipid bilayers.

跨膜的蛋白质导出是生命的关键过程。在原核生物中，多种蛋白质进化运输系统以促进两亲和亲水性蛋白的转移跨脂质疏水屏障的令人印象深刻的尺寸。这些系统中最简单的系统包括 ATP结合盒（ABC）转运蛋白，将ATP水解的能量利用驱动货物肽或蛋白质在细胞膜上的运动。在革兰氏正细菌，ABC转运蛋白导出抗菌或法定人数感应肽，这些肽用于在资源有限的条件下，赋予生物体具有生存优势。长该应用的术语目标是阐明含肽酶的构象动力学 ABC转运蛋白（PCAT），利用内置的半胱氨酸蛋白酶结构域裂开信号出口之前的货物肽序列。我们战略的前提是基于1） PCAT的最近的高分辨率结构，这些结构定义其分子结构并设置详细研究这些转运蛋白的机制的阶段易位和2）PI在采用最新电子状态中的往绩记录顺磁共振（EPR）光谱与诱变分析与活性运输商。具体目的旨在解决现场未解决的问题包括由ATP转换提供的交替访问的结构基础，决定因素货物蛋白特异性以及货物蛋白的结构和环境通过转运蛋白过渡。在过去的十年中，我们的方法与分子建模在揭示多饮用的结构动力学方面具有重要作用 ABC出口商并提供有关该家族内机械多样性的见解。这拟议的研究的重要性源于分子靶标在抗菌肽转运，细菌免疫，代表基本生化在脂质双层中导出蛋白质的过程。