Sphingolipids of the mycopathogen Sporothrix schenckii:: identification of a glycosylinositol phosphorylceramide with novel core GlcNH2α1 → 2Ins motif

Acidic glycosphingolipid components were extracted from the yeast form of the dimorphic mycopathogen Sporothrix schenckii. Two minor and the major fraction from the yeast form (Ss-Y1, -Y2, and -Y6. respectively) have been isolated. By a combination of 1- and 2-D H-1-nuclear magnetic resonance (NMR) spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and gas chromatography/mass spectrometry (GC/MS). Ss-Y6 was determined to be triglycosylinositol phosphorylceramide with a novel glycan structure, Man alpha1 --> 3Man alpha1 --> 6GlcNH(2)alpha1 --> 2Ins1-P-1Cer (where Ins = myo-inositol, P = phosphodiester), While the GlcNH(2)alpha1 --> 6Ins1-P-motif is found widely distributed in eukaryotic GPI anchors, the linkage GlcNH(2)alpha1 --> 2Insl-P- has not been previously observed in any glycolipid, Ss-Y1 and Ss-Y2 were both found to have the known glycan structure Man alpha1 --> 3Man alpha1 --> 2Ins1-P-1Cer, Together with the results of a prior study [Toledo et al, (2001) Biochem, Biophys. Res. Commun, 280, 19-24] which showed that the mycelium form expresses GIPCs with the structures Man alpha1 --> 6Ins1-P-1Cer and Man alpha1 --> 3Man alpha1 --> 6Ins1-P-1Cer, these results demonstrate that S, schenckii can synthesize glycosylinositol phosphorylceramides with at least three different core Linkages, (C) 2001 Federation of European Biochemical Societies, Published by Elsevier Science B.V. All rights reserved.