Facile synthesis of oligosaccharide probes for the analysis of protein-carbohydrate interactions

A strategy for facile oligosaccharide synthesis is described. It obviates chromatographic separation of intermediates and enables the isolation of desired oligomers with capture-release purification and reverse-phase silica-gel cartridge separation. As an example, preparation of monoglucosylated mannotetraose (Glc alpha1-->3Man alpha1-->2Man1alpha-->2Man1alpha-->3Man beta) was conducted. After sequential glycosylation, capture-release purification with Cys-resin, global deprotection, and reverse-phase silica-gel cartridge separation, the target pentasaccharide was isolated, while isolation of shorter oligomers that lack nonreducing-end residues (Man alpha1-->2Man1alpha-->2Man1alpha-->3Man beta, Man1alpha-->2Man1alpha-->3Man beta, Man1alpha-->3Man beta) was also achieved. These products were connected to a thiol-containing linker and immobilized on Au-coated chips. Their affinity to recombinant calreticulin was evaluated by quartz-crystal microbalance.