A study of the antibacterial mechanism of catechins: Isolation and identification of Escherichia coli cell surface proteins that interact with epigallocatechin gallate
A study of the antibacterial mechanism of catechins: Isolation and identification of Escherichia coli cell surface proteins that interact with epigallocatechin gallate
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DOI：
10.1016/j.foodcont.2013.03.016
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发表时间：
2013-10-01
期刊：
影响因子：
6
通讯作者：
Miyamoto, Takahisa
中科院分区：
文献类型：
--
作者：
Nakayama, Motokazu;Shimatani, Kanami;Miyamoto, Takahisa
儿茶素对各种微生物具有很高的抗菌活性。本研究以大肠杆菌为实验材料，探讨儿茶素类化合物的抑菌机理。透射电子显微镜分析显示，含有EGCg的沉积物仅在用EGCg处理的大肠杆菌细胞中的细胞表面的最外层的外膜上发现。基于这一观察结果，我们将重点放在外膜蛋白作为EGCg在E.杆菌双向电泳鉴定出16个斑点，这些斑点在用EGCg处理后与对照组相比消失或显示出明显降低的强度。其中，外膜孔蛋白OmpG酸表明碱性氨基酸Lys、Arg和His与EGCg强烈相互作用。与EGCg和OmpG的对接模拟显示，EGCg进入孔蛋白孔，并通过氢键结合到孔通道内表面上存在的Arg残基，导致孔蛋白功能的抑制。此外，E. EGCg处理的细胞对大肠杆菌的生长有抑制作用。综上所述，这些结果表明EGCg抑制了孔蛋白的主要功能，即小亲水分子如葡萄糖的被动转运，导致E.杆菌(C)2013爱思唯尔有限公司保留所有权利。
Catechins have high anti-bacterial activity against various microorganisms. In this study, the mechanism of anti-bacterial activity of catechins was investigated using Escherichia coli. Transmission electron microscope analysis revealed that deposits containing EGCg were found only on the outer membrane, which is the outermost layer of the cell surface, in E.coli cells treated with EGCg. Based on this observation, we focused on outer membrane proteins as targets of EGCg in E. coli. Two-dimensional electrophoresis identified 16 spots that had disappeared or showed markedly reduced intensity after treatment with EGCg compared to the control. Of these, an outer membrane porin protein, OmpG, acids suggested that the basic amino acids Lys, Arg, and His strongly interacted with EGCg. The docking simulation with EGCg and OmpG revealed that EGCg enters into the porin pore and binds to Arg residues present on the inner surface of the pore channel through hydrogen bonding, resulting in inhibition of the porin function. Furthermore, glucose uptake by E. coli was inhibited in cells treated with EGCg. Taken together, these results suggest that EGCg inhibits the major function of porin proteins, namely the passive transport of small hydrophilic molecules such as glucose, leading to growth inhibition of E. coli. (C) 2013 Elsevier Ltd. All rights reserved.