大肠杆菌分子伴侣蛋白HdeA和DegP协同抵抗酸胁迫的分子机制

项目名称： 大肠杆菌分子伴侣蛋白HdeA和DegP协同抵抗酸胁迫的分子机制

项目编号： No.31270804

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 生物科学

项目作者： 付新苗

作者单位： 北京大学

项目金额： 80万元

中文摘要： 哺乳动物的胃液为极端酸性（pH 1-3），是防止食物细菌感染的一道天然屏障，但仍然有少数细菌（例如大肠杆菌）能够适应这种酸胁迫。了解细菌的抗酸机制会加深我们对微生物生理和致病机理的理解，具有重要的科学意义和医学价值。本实验室近几年在揭示大肠杆菌膜间质抗酸系统作用机制方面取得了一定的进展，尤其是最近发现分子伴侣蛋白HdeA和双功能分子伴侣-蛋白酶DegP协同作用促进酸变性的蛋白复性，从而有效提高了细菌抗酸能力。本项目拟进一步研究这种协同抗酸的机制。我们将运用非天然氨基酸体内交联法鉴定HdeA和DegP在活细胞中的天然底物蛋白，并揭示DegP作为分子伴侣蛋白促进HdeA的天然底物蛋白复性的机制；另外，我们也将研究DegP作为蛋白酶发挥抗酸功能的作用机制。本项目的研究成果将为我们理解革兰氏阴性细菌（以大肠杆菌为代表）膜间质抗酸系统的普遍机制提供重要的依据和见解。

中文关键词： 细菌抗酸；分子伴侣；蛋白酶；DegP；HdeA

英文摘要： The extremely acidic environment (pH 1-3) of the mammalian stomach acts as a natural barrier against infections of food-borne pathogens, but a few bacteria strains (e.g. Escherichia coli) are still able to survive under such harsh conditions. It is of scientific and clinic significance to understand the acid resistance mechanism of bacteria as it will give us insights into the microbial physiology and pathogenesis. In the past few years, we have made a considerable progress in unraveling the acid resistance mechanism taking place in E. coli periplamic space, and in particular we recently found that molecular chaperone HdeA and chaperone-protease DegP cooperatively protect E.coli cells against acid stress. The present project is aiming to elucidate this cooperative mechanism deeply and comprehensively. We are planning to identify the natural client proteins of both HdeA and DegP by using in vivo photo-crosslinking with non-natural amino acids, to uncover the mechanism of DegP as a chaperone in assisting the refolding of natural client proteins of HdeA, and also to define the roles of DegP as a protease in the acid resistance. The outcomes of this project will give us insights into understanding the general mechanism underlying the acid resistance of gram-negative baceria (e.g.,E. coli) taking place in the peripla

英文关键词： bacterial acid resistance；molecualr chaperone；protease；DegP；HdeA