TABLE 1.
Structural characterization and relative abundance of the O-glycans on the colonic mucins from WT and KO mice
| Molecular ion [M-H]− | Proposed sequence/compositiona | Relative abundance (%)b |
|
|---|---|---|---|
| WT | KO | ||
| 587 | Gal-3(GlcNAc-6)GalNAcol | 9.89 | 8.39 |
| 530 | Fuc-Gal-3GalNAcol | 30.43 | 30.50 |
| 733a | Fuc-Gal-GlcNAc-GalNAcol | 2.14 | 1.30 |
| 733b | Fuc-Gal-3(GlcNAc-6)GalNAcol | 18.08 | 34.98 |
| 895a, 895b, 895d | Fuc, 2Gal, GlcNAc, GalNAcol | 3.58 | 2.46 |
| 895c | Gal-3(Gal-(Fuc-)GlcNAc-6)GalNAcol | 3.68 | 3.41 |
| 1041a | 2Fuc, 2Gal, GlcNAc, GalNAcol | 2.41 | 1.70 |
| 1041b | Fuc-Gal-3(Fuc-Gal-GlcNAc-6)GalNAcol | 10.27 | 16.16 |
| 667 | Gal-3(SO3−-6GlcNAc-6)GalNAcol | 2.05 | –c |
| 813 | Fuc-Gal-3(SO3−-6GlcNAc-6)GalNAcol | 9.13 | – |
| 975a | Gal-3(Fuc-Gal-(SO3−-6)GlcNAc-6)GalNAcol | 2.13 | – |
| 975b | Gal-3(Fuc-(SO3−-3/6)Gal-GlcNAc-6)GalNAcol | 0.99 | 1.10 |
| 1121 | Fuc-Gal-3(Fuc-Gal-(SO3−-6)GlcNAc-6)GalNAcol | 5.21 | – |
a For structural characterization, the following assumptions were made based on the reported structures of O-glycans: the hexose and deoxyhexose are Gal and fucose, respectively, the N-acetylhexosamine residue linked to N-acetylhexosamininitol is GlcNAc linked to GalNAcol, and the core 2 branch is formed after the core 1 structure is formed (46).
b The relative abundance was calculated by dividing the area of each peak by the total area of the peaks annotated in Fig. 6, A and B. Peaks of impurities, which did not produce secondary ions of oligosaccharide fragments in the MS/MS analysis, were excluded from the calculation.
c Not detected.