Li Hui, Wang Bao-Cheng, Xu Wen-Jiao, Lin Xiang-Min, Peng Xuan-Xian
Center for Proteomics, State Key Laboratory of Bio-Control, School of Life Sciences, Sun Yat-Sen University, Guangzhou, PRC.
J Proteome Res. 2008 Sep;7(9):4040-9. doi: 10.1021/pr800310y. Epub 2008 Aug 5.
Bacterial Outer membrane (OM) proteins involved in antibiotic resistance have been reported. However, little is known about the OM proteins and their interaction network regulating streptomycin (SM) resistance. In the present study, a subproteomic approach was utilized to characterize OM proteins of Escherichia coli with SM resistance. TolC, OmpT and LamB were found to be up-regulated, and FadL, OmpW and a location-unknown protein Dps were down-regulated in the SM-resistant E. coli strain. These changes at the level of protein expression were validated using Western blotting. The possible roles of the altered proteins involved in the SM resistance were investigated using genetic modified strains with the deletion of these altered genes. It is found that decreased and elevated minimum inhibitory concentrations and survival capabilities of the gene deleted strains and their resistant strains, Delta tolC, Delta ompT, Delta dps, Delta tolC-R, Delta ompT-R, Delta dps-R and Delta fadL-R, were correlated with the changes of TolC, OmpT, Dps and FadL at the protein expression levels detected by 2-DE gels, respectively. The results may suggest that these proteins are the key OM proteins and play important roles in the regulation of SM resistance in E. coli. Furthermore, an interaction network of altered OM proteins involved in the SM resistance was proposed in this report. Of the six altered proteins, TolC may play a central role in the network. These findings may provide novel insights into mechanisms of SM resistance in E. coli.
已有报道涉及抗生素耐药性的细菌外膜（OM）蛋白。然而，关于OM蛋白及其调节链霉素（SM）耐药性的相互作用网络却知之甚少。在本研究中，采用亚蛋白质组学方法来表征具有SM耐药性的大肠杆菌的OM蛋白。结果发现，在对SM耐药的大肠杆菌菌株中，TolC、OmpT和LamB上调，而FadL、OmpW和一种位置未知的蛋白Dps下调。使用蛋白质印迹法验证了这些蛋白质表达水平的变化。利用缺失这些改变基因的基因改造菌株研究了这些改变的蛋白质在SM耐药性中可能发挥的作用。结果发现，基因缺失菌株及其耐药菌株Delta tolC、Delta ompT、Delta dps、Delta tolC-R、Delta ompT-R、Delta dps-R和Delta fadL-R的最低抑菌浓度和生存能力的降低和升高，分别与2-DE凝胶检测到的TolC、OmpT、Dps和FadL在蛋白质表达水平的变化相关。这些结果可能表明这些蛋白质是关键的OM蛋白，在大肠杆菌SM耐药性的调节中发挥重要作用。此外，本报告还提出了一个涉及SM耐药性的改变的OM蛋白的相互作用网络。在这六种改变的蛋白质中，TolC可能在该网络中起核心作用。这些发现可能为大肠杆菌SM耐药机制提供新的见解。
