title: Glycosphingolipids of the model fungus Aspergillus nidulans: characterization of GIPCs with oligo-alpha-mannose-type glycans.
abstract: Aspergillus nidulans is a well-established nonpathogenic laboratory model for the opportunistic mycopathogen, A. fumigatus. Some recent studies have focused on possible functional roles of glycosphingolipids (GSLs) in these fungi. It has been demonstrated that biosynthesis of glycosylinositol phosphorylceramides (GIPCs) is required for normal cell cycle progression and polarized growth in A. nidulans (Cheng, J., T.-S. Park, A. S. Fischl, and X. S. Ye. 2001. Mol. Cell Biol. 21: 6198-6209); however, the structures of A. nidulans GIPCs were not addressed in that study, nor were the functional significance of individual structural variants and the downstream steps in their biosynthesis. To initiate such studies, acidic GSL components (designated An-2, -3, and -5) were isolated from A. nidulans and subjected to structural characterization by a combination of one-dimensional (1-D) and 2-D NMR spectroscopy, electrospray ionization-mass spectrometry (ESI-MS), ESI-MS/collision-induced decomposition-MS (MS/CID-MS), ESI-pseudo-[CID-MS]2, and gas chromatography-MS methods. All three were determined to be GIPCs, with mannose as the only monosaccharide present in the headgroup glycans; An-2 and An-3 were identified as di- and trimannosyl inositol phosphorylceramides (IPCs) with the structures Man alpha 1-->3Man alpha 1-->2Ins1-P-1Cer and Man alpha 1-->3(Man alpha 1-->6)Man alpha 1-->2Ins1-P-1Cer, respectively (where Ins = myo-inositol, P = phosphodiester, and Cer = ceramide). An-5 was partially characterized, and is proposed to be a pentamannosyl IPC, based on the trimannosyl core structure of An-3.
authors.affiliation: Department of Chemistry, University of New Hampshire, Durham, NH 03824-3598, USA.
authors.forename: Beau
authors.initials: B
authors.lastname: Bennion
authors.forename: Chaeho
authors.initials: C
authors.lastname: Park
authors.forename: Matthew
authors.initials: M
authors.lastname: Fuller
authors.forename: Rebecca
authors.initials: R
authors.lastname: Lindsey
authors.forename: Michelle
authors.initials: M
authors.lastname: Momany
authors.forename: Richard
authors.initials: R
authors.lastname: Jennemann
authors.forename: Steven B
authors.initials: SB
authors.lastname: Levery
mesh_terms: D001233:Aspergillus nidulans / Q000737:chemistry*; D002518:Ceramides / Q000032:analysis* / Q000737:chemistry*; D002855:Chromatography, Thin Layer; D006028:Glycosphingolipids / Q000032:analysis* / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008358:Mannose / Q000032:analysis* / Q000737:chemistry*; D015394:Molecular Structure; D010766:Phosphorylation; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D002518:Ceramides; D006028:Glycosphingolipids; D008358:Mannose