High-field (500 MHz) proton NMR has been used to elucidate the primary and secondary structures of glycosphingolipids (GSLs). Using 2-D J-correlated spectroscopy (2-D SECSY) which establishes scalar couplings of protons, the monosaccharide composition, anomeric configuration and aglycon structures of a GSL can be established. 2-D nuclear Overhauser effect spectroscopy (2-D NOE) then establishes through-space intra- and inter-residue couplings of cross-relaxing protons. We have found that each anomeric proton is involved in NOE couplings with inter- and intra-residue protons. The inter-residue coupling, resulting from interaction of protons across the glycosidic linkage, establishes the n-1 sugar residue and specific glycosidation site to which the n-residue is linked. When such information is known for each residue and is combined, the sequence of the core oligosaccharide is obtained. The sialylation-induced glycosidation shift is then used to establish the site of sialic acid residue attachment in a ganglioside molecule. We have also observed that the anomeric proton inter-residue NOE couplings can be used to suggest the preferred conformation of an oligosaccharide. We have found that the oligosaccharide residue of globoside exists in a unique and rather rigid conformation which could be stabilized by hydrogen bonds and van der Waals interactions. Since GSLs are known to have a receptor role and are implicated in cell-cell recognition, enzyme-substrate interaction and antigen-antibody interaction, the determination of their conformation should be useful in understanding their biological functions.
CITATION STYLE
Yu, R. K., Koerner, T. A., Demou, P. C., Scarsdale, J. N., & Prestegard, J. H. (1984). Recent advances in structural analysis of gangliosides: primary and secondary structures. Advances in Experimental Medicine and Biology, 174, 87–102. https://doi.org/10.1007/978-1-4684-1200-0_8
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