Sphingolipids of the mycopathogen Sporothrix schenckii: identification of a glycosylinositol phosphorylceramide with novel core GlcNH(2)alpha 1 -> 2Ins motif

Acidic glycosphingolipid components were extracted from the yeast form of t he dimorphic mycopathogen Sporothrix schenckii. Two minor and the major fra ction from the yeast form (Ss-Y1, -Y2, and -Y6. respectively) have been iso lated. By a combination of 1- and 2-D H-1-nuclear magnetic resonance (NMR) spectroscopy, electrospray ionization mass spectrometry (ESI-MS), and gas c hromatography/mass spectrometry (GC/MS). Ss-Y6 was determined to be triglyc osylinositol phosphorylceramide with a novel glycan structure, Man alpha1 - -> 3Man alpha1 --> 6GlcNH(2)alpha1 --> 2Ins1-P-1Cer (where Ins = myo-inosit ol, P = phosphodiester), While the GlcNH(2)alpha1 --> 6Ins1-P-motif is foun d 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 --> 3Ma n alpha1 --> 2Ins1-P-1Cer, Together with the results of a prior study [Tole do et al, (2001) Biochem, Biophys. Res. Commun, 280, 19-24] which showed th at the mycelium form expresses GIPCs with the structures Man alpha1 --> 6In s1-P-1Cer and Man alpha1 --> 3Man alpha1 --> 6Ins1-P-1Cer, these results de monstrate that S, schenckii can synthesize glycosylinositol phosphorylceram ides with at least three different core Linkages, (C) 2001 Federation of Eu ropean Biochemical Societies, Published by Elsevier Science B.V. All rights reserved.