应用电子顺磁共振技术探究结核分枝杆菌分泌系统内膜蛋白Rv3882c跨膜结构域的结构特征

项目名称： 应用电子顺磁共振技术探究结核分枝杆菌分泌系统内膜蛋白Rv3882c跨膜结构域的结构特征

项目编号： No.31500611

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 生物科学

项目作者： 于璐

作者单位： 中国科学院合肥物质科学研究院

项目金额： 20万元

中文摘要： 结核分枝杆菌的ESX-1分泌系统能使菌体分泌的致病因子、存活因子等蛋白质穿过其高度疏水致密的细胞被膜，对结核分枝杆菌的毒力和存活极为关键。因此，有关ESX-1分泌系统相关组成蛋白的结构分析对于理解结核杆菌感染机制具有非常重要的意义。Rv3882c蛋白是ESX-1分泌系统中一种重要的内膜蛋白，可能与其他组成蛋白共同形成通道类复合物，负责转运底物穿过细胞被膜，但目前其空间结构和确切的生物学功能尚不明确，仍亟待研究。本项目将结合位点特异性自旋标记与电子顺磁共振技术，通过获取Rv3882c蛋白跨膜结构域的运动性信息、易趋性信息以及在膜环境中的取向信息，综合分析得到Rv3882c蛋白跨膜结构域在膜环境中的三维结构模型。本项目的顺利开展，将为Rv3882c蛋白的结构研究提供重要依据，有助于进一步阐明结核分枝杆菌的分泌系统与致病机制，也为应用电子顺磁共振技术研究其他膜蛋白结构提供方法与思路。

中文关键词： 分枝杆菌分泌系统；膜蛋白；位点特异性自旋标记；电子顺磁共振；结构测定

英文摘要： The ESX-1 secretion system of Mycobacterium tuberculosis serves to secrete proteins, such as virulence factors and survival factors, across its highly hydrophobic and poorly permeable cell envelop, which is crucial for the virulence and survival of Mycobacterium tuberculosis. Therefore, structural investigation on component proteins of ESX-1 secretion system is very important for understanding the infection mechanisms of Mycobacterium tuberculosis. Rv0082c is a very important membrane protein of ESX-1 secretion system and is located on the inner membrane of Mycobacterium tuberculosis. It was predicted that Rv3382c forms a channel-like complex with other proteins and functions to transport the substrates across the mycobacterial cell envelope. However, the structure and function of this protein is still unclear. In this proposal, we are trying to characterize the structure of the transmembrane domain of membrane protein Rv3882c by combing Site Directed Spin Labelling (SDSL) technology and Electron Paramagnetic Resonance (EPR) spectroscopy. The acquired mobility, accessibility and orientation information in membrane will be integrated to derive a three dimensional structural model of the transmembrane domain of Rv3882c. Successful implementation of this project will not only yield valuable information for structural determination of Rv3882c, but also provide deeper insights of the protein secretion system and pathogenic mechanism of Mycobacterium tuberculosis. Also, this project will provide method of using EPR as the tool for structural studies of other membrane proteins.

英文关键词： Mycobacterium Secretion System;Membrane Protein;Site Directed Spin Labelling;Electron Paramagnetic Resonance;Structure Determination