Fig. 1.

Representation of the proteomics strategy used to identify surface-exposed proteins. Peptides and polypeptides released into the supernatant by surface digestion were either directly analyzed by LC/MS/MS (single digestion) or subjected to a second step of digestion with trypsin after a denaturing and reducing treatment (double digestion). MS/MS spectra were then searched against a database containing protein sequence data derived from the eight completely sequenced GBS strains and from the S. agalactiae section of the NCBInr database for protein identification.