FIG 5.
NanoLC-MS/MS analysis of the FlaB2 tryptic glycopeptide, T53–81, from the WT (a) and the Δmmp 0357 mutant strain (b). The FlaB2 tryptic peptide T53–81 contains one site of N-glycosylation (DSTEQVASGLQIMGISGYQAGTANANITK). The major carbohydrate oxonium ions are identified in the MS/MS spectra using symbols to indicate the sugar residues present: ◼, GalNAc; ●, GlcNAc3NAcA; ▲, ManNAc3NAmA6Thr; ◆, (5S)-2-acetamido-2,4-dideoxy-5-O-methyl-α-l-erythro-hexos-5-ulo-1,5-pyranose. The b and y ions arising from fragmentation of the peptide bonds are also shown. The structure of the tetrameric WT glycan has been described previously (17). The glycopeptide from the Δmmp0357 mutant strain (b) is modified with a disaccharide lacking the 3rd and 4th sugar residue of the WT glycan.