Isolation and characterization of a unique sulfated ganglioside, sulfated GM1a, from rat kidney

A novel class of sulfoglycosphingolipid, a sulfate analog of ganglioside, was isolated from mammals for the first time. This sulfated ganglioside was purified from rat kidney by column chromatographies on anion exchangers and silica beads. One-dimensional 1H NMR, compositional and permethylation analyses showed that this glycolipid has a Gg4Cer core with 1 mol each of sulfate ester and N- glycolylneuraminic acid (NeuGc) at C-3 of galactose. The major ceramide consisted of nonhydroxy fatty acids (24:0 and 22:0) and 4-hydroxysphinganine (t18:0), deduced from the compositional analysis and negative liquid secondary ion mass spectrometry (LSIMS). Mild acid hydrolysis and solvolysis produced compounds which correspond to Gg4Cer IV3-sulfate (SM1b) and II3NeuGcalpha-Gg4Cer (GM1a (NeuGc)), respectively. The abundant ions characteristic for sulfated mono- and disaccharides in high-energy collision-induced dissociation (CID) spectra were consistent with the structure at the non-reducing terminus, HSO3 -O- Hex -O- HexNAc- rather than the alternative structure, NeuGc -O- Hex -O- HexNAc-. The two-dimensional 1H NMR further evidenced the presence of a 3 -O- sulfated galactose in the molecule. From these results the complete structure was proposed to be HSO3-3Galbeta-3GalNAcbeta-4(NeuGcalpha-3)Galb eta-4Glcbeta-1Cer (II3NeuGcalpha-Gg4Cer IV3-sulfate).