Branched monosialo gangliosides of the lacto-series isolated from bovine erythrocytes: characterization of a novel ganglioside, NeuGc-isooctaosylceramide.
We report the isolation, purification, and structural characterization of three monosialo gangliosides (G-1, G-2, and G-3) from bovine erythrocytes. Each of the purified compounds migrates as a single band on thin-layer chromatography in three solvent systems. All three gangliosides contain ceramide (Cer) as the lipid protein, with d18:1 sphingosine as the predominant long-chain base and with C18:0, C18:1, C20:0, C20:1, and C22:1 fatty acids, as determined by gas chromatography. The structural characterization of the carbohydrate moieties of G-1, G-2, and G-3 involved glycosyl composition analysis, methylation studies, sequential exoglycosidase hydrolysis, and one-dimensional 1H NMR spectroscopy of the native gangliosides. Furthermore, the oligosaccharides were released from the sphingolipids by endoglycoceramidase and fully sequenced by one- and two-dimensional 1H NMR spectroscopy in conjunction with fast-atom-bombardment mass spectrometry and exoglycosidase treatment. The structures are as follows: [formula: see text] Gangliosides such as G-1, G-2, and G-3, with branched oligosaccharide chains comprising a number of N-acetyllactosamine (Gal-GlcNAc) moieties, are abundant in erythrocytes from various mammalian species. The simultaneous occurrence of sialic acid and alpha-galactose as terminal sugars in these gangliosides, however, is relatively rare. Specifically, G-1 represents a ganglioside with a novel structure.
Dasgupta
S
S
Department of Neurology, Medical University of South Carolina, Charleston 29425.
Hogan
E L
EL
Glushka
J
J
van Halbeek
H
H
D000581:Amidohydrolases; D000818:Animals; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002417:Cattle; D055572:Ceramidases; D004912:Erythrocytes / Q000737:chemistry*; D005732:Gangliosides / Q000096:biosynthesis* / Q000097:blood* / Q000737:chemistry* / Q000302:isolation & purification; D006017:Glycolipids / Q000097:blood / Q000302:isolation & purification; D006026:Glycoside Hydrolases; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry* / Q000302:isolation & purification; D016339:Spectrometry, Mass, Fast Atom Bombardment
D005732:Gangliosides; D006017:Glycolipids; C087076:N-glycolylneuraminic acid-isooctaosylceramide; D009844:Oligosaccharides; D006026:Glycoside Hydrolases; D000581:Amidohydrolases; D055572:Ceramidases