Yang Jun-Ning, Wang Chao, Guo Chang, Peng Xuan-Xian, Li Hui
Center for Proteomics, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, University City, Guangzhou 510006, People's Republic of China.
Mol Biosyst. 2011 Nov;7(11):3087-93. doi: 10.1039/c1mb05193h. Epub 2011 Aug 18.
Escherichia coli growth is a complicated process involved in many factors including the utilization of glucose. It has been reported that E. coli cell growth rate is closely related with glucose concentrations in the cell culture medium. However, the protein regulation networks in response to glucose concentration changes are largely unknown. In the present study, a sub-proteomic methodology has been utilized to characterize alterations of E. coli OM proteins in response to 0.02, 0.2 and 2% concentrations of glucose. In comparison with E. coli cells treated with 0.2% glucose concentration, downregulation of FhuE, FepA, CirA, TolC and OmpX and upregulation of LamB, FadL, OmpF, OmpT and Dps were detected in the E. coli cells treated with 0.02% glucose, and a decrease of TolC, LamB, OmpF, OmpT, OmpX, Dps and elevation of FhuE, FepA, CirA, YncD, FadL and MipA were found in 2% glucose. TolC, LamB and OmpT showed more important roles than other altered OM proteins. Furthermore, the interaction among these altered OM proteins was investigated, and protein interaction networks were characterized. In the networks, all proteins were interacted and regulated by others. TolC, LamB and Dps were the top three proteins that regulated more proteins than others, whereas CirA and OmpT were the top two proteins that were regulated by others. The protein networks could be modified correspondingly with the changes of glucose concentrations. The modifications included the addition of new OM proteins or the change of regulation direction. These findings suggest the important roles of the bacterial OM protein network in E. coli's responses to glucose concentration changes and other environment stresses.
大肠杆菌的生长是一个复杂的过程，涉及许多因素，包括葡萄糖的利用。据报道，大肠杆菌细胞的生长速率与细胞培养基中的葡萄糖浓度密切相关。然而，响应葡萄糖浓度变化的蛋白质调控网络在很大程度上尚不清楚。在本研究中，已利用亚蛋白质组学方法来表征大肠杆菌外膜蛋白在0.02%、0.2%和2%葡萄糖浓度下的变化。与用0.2%葡萄糖浓度处理的大肠杆菌细胞相比，在用0.02%葡萄糖处理的大肠杆菌细胞中检测到FhuE、FepA、CirA、TolC和OmpX的下调以及LamB、FadL、OmpF、OmpT和Dps的上调，而在2%葡萄糖中发现TolC、LamB、OmpF、OmpT、OmpX、Dps减少以及FhuE、FepA、CirA、YncD、FadL和MipA升高。TolC、LamB和OmpT比其他改变的外膜蛋白发挥更重要的作用。此外，研究了这些改变的外膜蛋白之间的相互作用，并表征了蛋白质相互作用网络。在这些网络中，所有蛋白质都相互作用并受其他蛋白质调控。TolC、LamB和Dps是调控其他蛋白质数量最多的前三种蛋白质，而CirA和OmpT是受其他蛋白质调控最多的前两种蛋白质。蛋白质网络可随葡萄糖浓度的变化而相应改变。这些改变包括新外膜蛋白的添加或调控方向的改变。这些发现表明细菌外膜蛋白网络在大肠杆菌对葡萄糖浓度变化和其他环境应激反应中的重要作用。
