Figure 1:

Detection of metabolically engineered non-natural glycans by chemical tag free glycoproteomics and glycomics. (a) The membrane proteins were enriched, reduced/alkylated, and digested by protease. The resulting glycopeptides were enriched for glycoproteomics by LC-MS/MS whereas the glycans were released by β-elimination followed by acetylation for glycomics; (b) For glycoproteomics, the LC-MS/MS chromatogram is extracted for the desired non-natural glycan based on the presence of oxonium ions in the spectra, detected the N-glycosylation pattern and thereby the non-natural glycan structures and searched for both natural and non-natural glycan bearing glycopeptides. O-glycopeptides are identified by the direct search of the extracted chromatogram.