A New Extended Globoglycolipid Carrying the Stage Specific Embryonic Antigen-1 (SSEA-1) Determinant in Mouse Kidney

Abstract

Two neutral glycolipids carrying the stage specific embryonic antigen-1 (SSEA-1) and SSEA-3 determinants, respectively, were purified from mouse kidney by a combination of column chromatographies and droplet counter-current chromatography. The structures of the glycolipids (GL-X and GL-Y) were determined by means of GLC, ¹H-NMR spectroscopy, negative-ion fast atom bombardment mass spectrometry, a methylation study, and sequential degradation. GL-X was demonstrated to be galactosylβ1-3globotetraosylceramide, the structure of which had already been characterized to be that of SSEA-3 by Kannagi et al. ((1983) J. Biol. Chem. 258, 8934-8942). GL-Y was a new glycolipid containing fucose, galactose, glucose, N- cetylgalactosamine, and N-acetylglucosamine in a molar ratio of 1:4:1:1:1. The methylation study results indicated that it contained 3 mol of terminal sugars composed of 2 mol of galactose and 1 mol of fucose with two branching points at N-acetylgalactosamine and N-acetylglucosamine. From the data obtained by ¹H-NMR spectroscopy, mass spectrometry, and a binding assay using an antiSSEA-1 monoclonal antibody (PM81) cloned by Ball et al. ((1983) J. Immunol. 130, 2937-2941), we propose the structure of GL-Y to be
Galβ1-4GlcNAcβ1-6GalNAc/β1-3Galα1-4Galβ1-4Glcβ1-ceramide. ³-Fucα1 ³-Galβ1
This is the first report on the isolation and characterization of a glycolipid carrying the SSEA-1 determinant on its globo-core structure.