Journal of Proteomics ( IF 2.8 ) Pub Date : 2020-11-04 , DOI: 10.1016/j.jprot.2020.104025 Ricardo Monteiro 1 , Ingrid Chafsey 2 , Valentin Ageorges 2 , Sabine Leroy 2 , Christophe Chambon 3 , Michel Hébraud 4 , Valérie Livrelli 5 , Mariagrazia Pizza 6 , Alfredo Pezzicoli 6 , Mickaël Desvaux 2
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Among diarrheagenic E. coli (DEC), enterohaemorrhagic E. coli (EHEC) are the most virulent anthropozoonotic agents. The ability of bacterial cells to functionally interact with their surrounding essentially relies on the secretion of different protein effectors. To experimentally determine the repertoire of extracytoproteins in E. coli O157:H7, a subproteomic analysis was performed not only considering the extracellular milieu but the cell surface and outer membrane vesicles. Following a secretome-based approach, the proteins trafficking from the interior to the exterior of the cell were depicted considering cognate protein transport systems and subcellular localisation. Label-free quantitative analysis of the proteosurfaceome, proteovesiculome and exoproteome from E. coli O157:H7 grown in three different nutrient media revealed differential protein expression profiles and allowed defining the core and variant subproteomes. Network analysis further revealed the higher abundance of some protein clusters in chemically defined medium over rich complex medium, especially related to some outer membrane proteins, ABC transport and Type III secretion systems. This first comprehensive study of the EHEC secretome unravels the profound influence of environmental conditions on the extracytoplasmic proteome, provides new insight in the physiology of E. coli O157:H7 and identifies potentially important molecular targets for the development of preventive strategies against EHEC/STEC.
Significance
Escherichia coli O157:H7 is responsible for severe diarrhoea especially in young children. Despite years of investigations, the global view of the extracytoplasmic proteins expressed in this microorganism was eluded. To provide the first comprehensive view of the secretome landscape of E. coli O157:H7, the exoproteome, proteosurfaceome and proteovesiculome were profiled using growth conditions most likely to induce changes in bacterial protein secretion. The profound influence of growth conditions on the extracytoplasmic proteome was unravelled and allowed identifying the core and variant subproteomes. Besides new insight in the physiology of enterohaemorrhagic E. coli, these proteins potentially constitute important molecular targets for the development of preventive strategies.
中文翻译：
大肠杆菌 O157:H7 的分泌组景观：破译细胞表面、外膜囊泡和细胞外亚蛋白质组
在引起腹泻的大肠杆菌（DEC）中，肠出血性大肠杆菌（EHEC）是最致命的人畜共患病病原体。细菌细胞与其周围环境进行功能性相互作用的能力主要依赖于不同蛋白质效应物的分泌。实验确定大肠杆菌中的胞外蛋白库O157:H7，进行了亚蛋白质组学分析，不仅考虑了细胞外环境，还考虑了细胞表面和外膜囊泡。按照基于分泌组的方法，考虑到同源蛋白质转运系统和亚细胞定位，描述了从细胞内部到外部运输的蛋白质。来自大肠杆菌的蛋白质表面组、蛋白质囊泡组和外蛋白质组的无标记定量分析在三种不同营养培养基中生长的 O157:H7 揭示了不同的蛋白质表达谱，并允许定义核心和变体亚蛋白质组。网络分析进一步揭示了化学成分确定的培养基中某些蛋白质簇的丰度高于丰富的复杂培养基，特别是与某些外膜蛋白、ABC 转运和 III 型分泌系统有关。这是对 EHEC 分泌组的首次全面研究，揭示了环境条件对胞质外蛋白质组的深远影响，为大肠杆菌O157:H7 的生理学提供了新的见解，并确定了制定针对 EHEC/STEC 的预防策略的潜在重要分子靶点。
意义
大肠杆菌O157:H7 是造成严重腹泻的原因，尤其是在幼儿中。尽管进行了多年的研究，但对这种微生物中表达的胞质外蛋白的总体看法仍被忽视。为了提供大肠杆菌O157:H7分泌组景观的第一个全面视图，使用最有可能诱导细菌蛋白质分泌变化的生长条件对外蛋白质组、蛋白质表面组和蛋白质囊泡组进行了分析。生长条件对胞质外蛋白质组的深远影响被揭示，并允许识别核心和变体亚蛋白质组。除了对肠出血性大肠杆菌生理学的新见解，这些蛋白质可能构成制定预防策略的重要分子靶点。
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