The probiotic[i] Propionibacterium freudenreichii[/i] surface proteome

摘要: Surface proteins are key actors of the complex interactions between bacteria (pathogens, commensals or symbionts) and their host. In beneficial (probiotic) bacteria, they participate in competition with pathogens, adhesion to host cells, immunomodulation. We investigated such bacterium Propionibacterium freudenreichii, consumed both Swiss-type cheeses probiotic preparations. P. freudenreichii genome was sequenced annotated, localization encoded predicted using SurfG+. A combination 3 biochemical methods confirmed surface exposure proteins: shedding, shaving labelling. Shedding consisted extraction cell-wall associated guanidine, followed by trypsinolysis extracted proteins. Shaving enzymatic hydrolysis protruding which were accessible trypsin situ on live bacteria. For labeling, an NHS-ester-cyanine added order label proteins, prior 2-D electrophoresis detection fluorescent protein spots. methods, resulting tryptic peptides identified NanoLC-MS/MS a Q-TOF mass spectrometer This allowed identification layer type-proteins, lipoproteins, cell wall, membrane, be secreted, as well moonlighting cytoplasmic. Some these known modulation immune response probiotics. work constitutes decisive step elucidation ability interact cells understanding sorting this bacterium.