Proteomic analysis of the exoproteome and surfaceome of Lactiplantibacillus plantarum CRL681: mechanisms of competitive exclusion against enterohemorrhagic Escherichia coli

The study focuses on the proteomic analysis of the exoproteome and surfaceome of Lactiplantibacillus plantarum CRL681, aiming to explore the molecular mechanisms underlying its antagonistic capacity against enterohemorrhagic Escherichia coli (EHEC). More than 600 proteins were identified by mass spectrometry across both proteomes, of which 285 were characterized as part of the secretome through a detailed analysis with bioinformatics tools and bibliographic references. The analysis of these proteins allowed us to conclude that some of them are involved in functions like energy metabolism, nutrient transport, cell adhesion, genetic information processing, and signaling. Additionally, moonlighting proteins were observed, which possess bacterial adhesion capabilities that may contribute to the L. plantarum CRL681 antagonistic actions against EHEC. This group included ribosomal proteins and peptidoglycan hydrolases, that would be responsible for the EHEC cell lysis observed under in vitro experimental conditions. Furthermore, the co-culture of the CRL681 strain with E. coli revealed differential expression of key proteins, such as the overexpression of glutathione reductase, involved in maintaining redox balance. This proteomic study is a step forward in the understanding of the molecular mechanisms underlying the antagonistic capacity of L. plantarum CRL681 against EHEC.

本研究聚焦植物乳杆菌（Lactiplantibacillus plantarum）CRL681的分泌蛋白质组与表面蛋白质组蛋白质组学分析，旨在探究其对抗肠出血性大肠埃希菌（enterohemorrhagic Escherichia coli，EHEC）拮抗能力背后的分子机制。通过质谱技术在两组蛋白质组中共鉴定出600余种蛋白质，其中经生物信息学工具与文献参考的详细分析，将285种蛋白质归类为分泌蛋白质组的组成部分。对上述蛋白质的分析结果显示，部分蛋白质参与能量代谢、营养转运、细胞黏附、遗传信息加工以及信号传导等生物学功能。此外，研究还观察到兼职蛋白质，这类蛋白质具备细菌黏附能力，可能助力植物乳杆菌CRL681发挥对抗EHEC的拮抗作用。该类蛋白质包括核糖体蛋白与肽聚糖水解酶，可介导体外实验条件下观察到的EHEC细胞裂解过程。进一步将CRL681菌株与大肠杆菌共培养的实验显示，关键蛋白质存在差异表达现象，例如参与维持氧化还原平衡的谷胱甘肽还原酶出现过表达。本蛋白质组学研究为解析植物乳杆菌CRL681对抗EHEC的拮抗能力背后的分子机制迈出了重要一步。