Distinctive MS/MS Fragmentation Pathways of Glycopeptide-Generated Oxonium Ions Provide Evidence of the Glycan Structure.

• Post-translational glycosylation of proteins play key roles in cellular processes and the site-specific characterisation of glycan structures is critical to understanding these events. Given the challenges regarding identification of glycan isomers, glycoproteomic studies generally rely on the assumption of conserved biosynthetic pathways. However, in a recent study, we found characteristically different HexNAc oxonium ion fragmentation patterns that depend on glycan structure. Such patterns could be used to distinguish between glycopeptide structural isomers. To acquire a mechanistic insight, deuterium-labelled glycopeptides were prepared and analysed. We found that the HexNAc-derived m/z 126 and 144 oxonium ions, differing in mass by H2 O, had completely different structures and that high-mannose N-glycopeptides generated abundant Hex-derived oxonium ions. We describe the oxonium ion decomposition mechanisms and the relative abundance of oxonium ions as a function of collision energy for a number of well-defined glycan structures, which provide important information for future glycoproteomic studies.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Andra medicinska och farmaceutiska grundvetenskaper (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Other Basic Medicine (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Klinisk laboratoriemedicin (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Clinical Laboratory Medicine (hsv//eng)

Keyword

Mass spectrometry

glycopeptide

oxonium ions

Publication and Content Type

ref (subject category)

art (subject category)