H-1 and C-13 NMR assignments for the glycans in glycoproteins by using H-2/C-13-labeled glucose as a metabolic precursor

In order to understand the role of the glycans in glycoproteins in solution , structural information obtained by NMR spectroscopy is obviously required . However, the assignment of the NMR signals from the glycans in larger gly coproteins is still difficult, mainly due to the lack of appropriate method s for the assignment of the resonances originating from the glycans. By usi ng [U-C-13(6),H-2(7)]glucose as a metabolic precursor, we have successfully prepared a glycoprotein whose glycan is uniformly labeled with C-13 and pa rtially with D at the sugar residues. The D to H exchange ratios at the C1- C6 positions of the sugar residues have been proven to provide useful infor mation for the spectral assignments of the glycan in the glycoprotein. This is the first report on the residue-specific assignment of the anomeric res onances originating from a glycan attached to a glycoprotein by using the m etabolic incorporation of hydrogen from the medium into a glycan labeled wi th [U-C-13(6),H-2(7)]glucose.