Chemoenzymatic Synthesis of α-Dystroglycan O-Mannose Glycans

O-mannosylation is a conserved common post-translational modification of various eukaryotic proteins. The O-mannose glycans account for up to 30% of total O-glycans in mammalian brain tissues. However, the α-dystroglycan (α-DG) is the only O-mannosylated protein that has been extensively studied. This review covers the biosynthetic pathways and biological roles of O-mannose glycans, as well as the chemical and chemoenzymatic strategies developed for the synthesis of O-mannose core M1, core M2 and core M3 glycans.