银离子和纳米银生物靶点的鉴定及其抗菌活性机理的深入探究

Silver cation has been used as an antimicrobial agent for centuries. Its mode of action is largely attributed to the ability of silver to interact with various cellular biomolecules. Silver nanoparticles (AgNPs) have also been extensively studied as broad-spectrum antimicrobial agents, and the release of ions is a driving force behind their antimicrobial properties. However, there appears lack of studies on the identification of cellular Ag-binding proteins at the proteome-wide scale. In this project, we intend to identify the protein targets of both silver cation and AgNPs in gram-positive (S. aureus, newman) and gram-negative (E. coli, K-12 MG1655) bacteria using a home-made tailored GE-ICP-MS system, and to functionally validate the potential protein targets both in vivo and in vitro. Moreover, we will evaluate silver-induced bacterial responses at both the transcriptome and metabolome levels. Through an integrative omics point of view, we will produce a comprehensive picture of the mechanisms of toxicity of silver cation and AgNPs to bacteria.

银离子作为抗菌试剂已有几百年历史，其抗菌活性机理极大程度上来自于银离子与细胞内各类生物大分子的相互作用。近年来，纳米银作为广谱抗菌试剂亦受到了广泛关注。其中，银离子的释放对纳米银的抗菌活性起到关键作用。然而目前对于银离子和纳米银在细菌内的主要靶点蛋白尚未明确。本项目拟利用改进后的凝胶电泳柱-电感耦合等离子体质谱联用系统，对银离子和纳米银在金黄葡萄球菌和大肠杆菌中的结合蛋白进行全蛋白组层面的识别，且在细胞内和细胞外分别对银与其潜在靶点蛋白的结合进行验证。同时，对银离子和纳米银诱导细菌转录组和代谢组变化情况进行系统性分析。目标是通过整合组学和分子生物学实验结果，对银离子和纳米银的抗菌活性机理有全面深入的认识。

银离子作为抗菌试剂已有几百年历史，其抗菌活性机理极大程度上来自于银离子与细胞内各类生物大分子的相互作用。然而目前对于银离子和纳米银在细菌内的主要靶点蛋白和作用机制尚未明确。在本项目中，我们开发了一种二维凝胶电泳柱-电感耦合等离子体质谱在线联用系统，对银离子在金黄葡萄球菌和大肠杆菌中的结合蛋白进行全蛋白组层面的识别，首次报道并验证了多个能够银离子的细菌靶标蛋白，包括金黄色葡萄球菌的碳源代谢调控蛋白A和大肠杆菌的甘油醛-3-磷酸脱氢酶。另一方面，通过对银离子诱导细菌转录组和代谢组变化进行情况的分析，发现了银离子可以通过影响细菌的糖酵解，三羧酸循环等代谢通路而发挥抗菌作用，该项研究的成果使得我们对银离子的抗菌活性机理有更加全面而深入的认识。