A 500-MHz 1H-N.M.R. study of oligosaccharides derived from gangliosides by ozonolysis - alkaline fragmentation

Abstract

The structural-reporter-group resonances in the 1H-n.m.r. spectra of a series of ganglioside-derived oligosaccharides are completely assigned. The three different types of sialic acid residues which may occur in these compounds could be adequately characterized. They are distinguishable on the basis of the set of chemical shifts of their H-3a and H-3e atoms. The mutual influence of GalNAc β-(1→4) and Neu5Ac α-(2→3), both linked to the same Gal residue, on the 1H-n.m.r. parameters of each other, reflects a well-defined solution confirmation, which is held to be responsible for the resistance of this 'internal' sialic acid towards various sialidases.