FIGURE 11.

Exogenously supplemented GalNAc or GalNGc gives rise to novel O-glycan structures in CHO cells. O-Glycans from CHO ldl-D cells were isolated and analyzed by MALDI as described in the legend of Fig. 9. N-Glycolylhexosamine (HexNGc) is depicted as red squares to extend the common monosaccharide code (69). Peak assignment was based on MS/MS fragmentation analysis for these novel O-glycan structures. A, zoom into MALDI spectrum of O-glycans isolated from GalNAc-fed ldl-D cells (m/z 760–850). B, fragmentation pattern of m/z 779.47 ion from GalNAc-fed ldl-D cells. C, zoom into MALDI spectrum of O-glycans isolated from GalNGc-fed ldl-D cells (m/z 760–850). D, MS/MS fragmentation pattern of m/z 809.49 ion from GalNGc-fed ldl-D cells. Most relevant differences in the MS/MS fragment ions pointing toward the presence of HexNGc are highlighted with arrows.