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.

蛋白质跨膜输出是生命的关键过程。在原核生物中，多种蛋白质运输系统的发展是为了促进两亲性和亲水性蛋白质的转移跨越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包括 ATP 结合盒 (ABC) 转运蛋白，利用 ATP 水解的能量为货物肽或蛋白质穿过细胞膜的运动提供动力。革兰氏阳性细菌、ABC 转运蛋白输出抗菌肽或群体感应肽，用于赋予有机体在资源有限的条件下生存的优势。长的本申请的长期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来切割信号出口前货物肽的序列。我们战略的前提基于 1) 最近 PCAT 的高分辨率结构定义了它们的分子结构并设定了详细研究这些转运蛋白使蛋白质发挥作用的机制的阶段易位和 2) PI 在最先进电子应用中的跟踪记录顺磁共振（EPR）波谱与诱变分析相结合，以活性运输者。具体目标旨在解决该领域未解答的问题包括由 ATP 周转驱动的交替访问的结构基础、决定因素货物蛋白的特异性，以及货物蛋白的结构和环境通过传输器进行转换。在过去的十年中，我们的方法集成了分子模型有助于揭示多药的结构动力学 ABC 出口商并提供对该系列内机械多样性的见解。这拟议研究的意义源于连接处的分子靶标抗菌肽转运、细菌免疫，代表一种基本的生化物质蛋白质跨脂质双层输出的过程。