Figure 1.

Typical plant-derived N-glycan structures. In plant cells, the GnGnXF structure accounts for the majority of the N-glycoforms. The second most abundant structure is the paucimannosidic MMXF with truncated terminal GlcNAc residues generated by specific β-N-acetylhexosaminidases located at either the vacuole or the plasma membrane/apoplast. Although relatively low in abundance, the (FA)(FA)XF structure with terminal Lewis A (Le^a) epitopes generated in the trans Golgi compartment is commonly found in plants. All three N-glycoforms presumably carry plant specific α1,3-linked fucose and β1,2-linked xylose residues. GlcNAc, N-acetylglucosamine; Man, Mannose; Fuc, Fucose; Xyl, Xylose; Gal, Galactose.