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

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Abstract
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 II3NeuGcα-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-HexO-HexNAc- rather than the alternative structure, NeuGcO-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 HSO3-3Galβ-3GalNAcβ-4(NeuGcα-3)Gal β-4Glcβ-1Cer (II3NeuGcα-Gg4Cer IV3-sulfate).