2-DE and MS analysis of key proteins in the adhesion of Lactobacillus plantarum, a first step toward early selection of probiotics based on bacterial biomarkers.

The identification of cell components involved in probiotic activities is a challenge in current probiotic research. In this work, a new approach based on proteomics as an analytical tool for the identification of characteristic protein profiles related to adhesion to mucin as a model probiotic property was used. Three Lactobacillus plantarum strains with different adhesion rates were used for proteomic analysis: L. plantarum WHE 92 (15.9%), L. plantarum 299 v (9.1%) and L. plantarum CECT 4185 (1.4%). Cell wall extracts were subjected to proteomic analysis of differential protein expression using 2-DE, tryptic digestion, chip-LC-QTOF mass analysis and protein identification using database search. Several proteins, previously reported to be involved in bacterial adhesion: elongation factor EF-Tu, GroEL chaperonin, molecular chaperone DnaK and glyceraldehyde-3-phosphate dehydrogenase were found to be overexpressed in the cell wall proteome of the highly adhesive strain L. plantarum WHE 92. The overexpression of two spots containing GroES co-chaperonin in the most adhesive strain also suggested the involvement of this protein in the adhesion process. The association of proteomic profiles and proteins with particular probiotic properties opens the way for the use of such profiles and proteins as bacterial biomarkers for the properties of bacteria but probably also for their potential health effects.