Figure 1.

The pivotal role of the core pentasaccharide in N-glycoproteins. (a) The conserved core pentasaccharide motif, (Man₃GlcNAc₂ shown in gray box), is attached to asparagine residues of glycoproteins (N, S, and T denote asparagine, serine, and threonine, X denotes any amino acid but not proline). Proteins are cotranslationally modified with a tetradecasaccharide which is tailored by glycosyl-hydrolase and transferase enzymes to create diverse glycans with varying antennae but all based upon the conserved core pentasaccharide (gray box). (b) The structures and symbol representations of the core pentasaccharide 4 and the building blocks 1–3 from key regions of 4 used in this study. The naming convention A–E is used in this manuscript to identify the individual glycosyl residues. The site of the benign chromophore used in this study mimics the location of the protein scaffold or truncated glycan (shown by a red star).