YdiV促ClpXP蛋白酶降解FlhDC复合物的分子机制研究

项目名称： YdiV促ClpXP蛋白酶降解FlhDC复合物的分子机制研究

项目编号： No.31500050

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： 李冰清

作者单位： 山东省医学科学院

项目金额： 20万元

中文摘要： ClpXP蛋白酶是细胞生命活动的重要调控蛋白，其通过降解重要功能蛋白发挥作用。而ClpXP如何招募辅助因子发挥蛋白降解功能是国内外关注的热点。其中，YdiV蛋白协助ClpXP降解“鞭毛合成总开关”FlhDC复合体成为细菌运动行为调控的重要现象。但这一现象的分子机理还未被阐明，极大制约了ClpXP在细菌行为调控方面的研究进展。本课题组在前期确定YdiV、FlhD及ClpX亚基三者存在直接互作的基础上，拟通过测定YdiV-ClpX及YdiV-FlhD-ClpX的晶体结构，进一步将YdiV确定为ClpXP调控鞭毛的特异辅助因子。通过与已知结构的叠合、对比，清晰完整地描绘出底物识别和酶催化过程中蛋白间的动态互作与构形变化。并基于结构构建功能缺失突变体，比较野生型和突变体的酶活及细菌移动性，系统地阐述降解过程的分子机理。为ClpXP底物识别机制研究提供重要数据，也为细菌鞭毛调控提供了重要的理论基础。

中文关键词： 酶的结构与功能；底物吸附结合机制；底物识别机制；协同作用

英文摘要： ClpXP protease is an important regulatory protein of cellular activities by hydrolyzing many function proteins such as crucial transcription factors. The mechanism by which ClpXP protease recruits adaptors and recognizes substrates is a hot focus. Among them, An important phenomenon has recently been found that with the help of YdiV, ClpXP can regulate the motive behavior of bacteria by degrading flagellum biosynthesis master switch--FlhDC complex. But the molecular mechanism of this phenomenon has not been elucidated, which greatly restricts the research progress on bacterial behavior regulation of ClpXP. Our previous research has identified that YdiV, FlhD and ClpX interact with each other directly. In this project, we are going to determine the crystal structure of YdiV-ClpX and YdiV-FlhD-ClpX complex. Based on the structure of those complex, we will confirm the sites and types of protein-protein interact surface.Compared with the structures of ClpXP, YdiV and FlhDC in Protein Data Bank, we will analyze dynamic interaction of YdiV, ClpXP and FlhDC in this degradation process. Structural analysis combined with necessary biochemical and in vivo experiments will reveal the mechanism of this degradation process at the molecular level. This study will provide important data for the substrate recognition and binding mechanism of ClpXP protease, but also provides theoretical basis for the research of bacterial flagella regulation.

英文关键词： Structure and function of ClpXP protease;Mechanism of substrate adsorption;Mechanism of substrate recognition;Synergistic effect