Lin Xiang-Min, Li Hui, Wang Chao, Peng Xuan-Xian
Center for Proteomics, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
J Proteome Res. 2008 Jun;7(6):2399-405. doi: 10.1021/pr800073c. Epub 2008 Apr 26.
The worldwide emergence of antibiotic-resistant bacteria poses a serious threat to human health. To understand the mechanisms of the resistance is extremely important to the control of these bacteria. In the current study, proteomic methodologies were utilized to characterize OM proteome of Escherichia coli with nalidixic acid (NA) resistance. The OM proteins TolC, OmpT, OmpC and OmpW were found to be up-regulated, and FadL was down-regulated in the NA-resistant E. coli strains. The changes at the level of protein expression were validated using Western blotting. Furthermore, the possible roles these altered proteins played in regulation of NA resistance were investigated using genetically modified strains with the deletion of these genes. The results obtained from functional characterization of these genetically modified strains suggest that TolC and OmpC may play more important roles in the control of NA resistance than other OM proteins identified. To gain better understanding of the mechanisms of NA resistance, we also characterized the role of the two-component system EnvZ/OmpR which is responsible for the regulation of OmpC and OmpF expression in response to NA resistance using their genetically modified strains. Our results suggest that OmpF and the EnvZ/OmpR are also important participants of the pathways regulating the NA resistance of E. coli.
全球范围内抗生素耐药菌的出现对人类健康构成了严重威胁。了解耐药机制对于控制这些细菌极为重要。在当前研究中，利用蛋白质组学方法对耐萘啶酸（NA）的大肠杆菌外膜蛋白质组进行了表征。发现外膜蛋白TolC、OmpT、OmpC和OmpW在耐NA的大肠杆菌菌株中上调，而FadL下调。使用蛋白质印迹法验证了蛋白质表达水平的变化。此外，利用缺失这些基因的基因工程菌株研究了这些改变的蛋白质在NA耐药调控中可能发挥的作用。从这些基因工程菌株的功能表征获得的结果表明，TolC和OmpC在控制NA耐药方面可能比其他已鉴定的外膜蛋白发挥更重要的作用。为了更好地理解NA耐药机制，我们还利用其基因工程菌株表征了双组分系统EnvZ/OmpR在响应NA耐药时对OmpC和OmpF表达调控中的作用。我们的结果表明，OmpF和EnvZ/OmpR也是大肠杆菌NA耐药调控途径的重要参与者。
