STRUCTURAL CHARACTERIZATION OF A NOVEL MONO-SULFATED GANGLIOTRIAOSYLCERAMIDE CONTAINING A 3-O-SULFATED N-ACETYLGALACTOSAMINE FROM RAT-KIDNEY

A novel mono-sulfated glycosphingolipid based on the gangliotriaose co re structure was isolated from rat kidney. The isolation procedure inv olved extraction of lipids with chloroform/methanol, mild alkaline met hanolysis,column chromatographies with anion exchangers and silica bea ds. The structure was characterized by compositional analysis, FTIR sp ectroscopy, methylation analysis, H-1-NMR spectroscopy and negative-io n liquid secondary ion mass spectrometry (LSIMS) using the intact glyc olipid and its desulfation product. The two dimensional chemical shift correlated spectroscopy provided information on the sugar sequence as well as anomeric configurations, and indicated the presence of a 3-O- sulfated N-acetylgalactosamine within the molecule. Negative-ion LSIMS with high- and low-energy collision-induced dissociation defined the sugar sequence and ceramide composition, confirming the presence of a sulfated N-acetylgalactosamine at the non-reducing terminus. From thes e results, the complete structure was proposed to be HSO3-3GalNA beta 1-4Gal beta 1-4Glc beta 1-1Cer (Gg(3)Cer III3-sulfate, SM2b).