title: Structures of glycosylphosphatidylinositol membrane anchors from Saccharomyces cerevisiae.
abstract: Metabolic labeling studies suggest that Saccharomyces cerevisiae contains many glycoproteins that are anchored in the lipid bilayer by glycosylphosphatidylinositol membrane anchors. Membrane anchors were purified from a crude yeast membrane protein fraction and analyzed by two-dimensional 1H-1H NMR, fast atom bombardment-mass spectrometry, compositional and methylation linkage analyses, as well as chemical and enzymatic modifications. The yeast glycosylphosphatidylinositol anchors consist of the following structures: ethanolamine-PO4-6(R-2)Man alpha 1-2Man alpha 1-6Man alpha 1-4Glc-NH2 alpha 1-6myo-inositol-1-PO4-lipid, where R is mainly Man alpha 1- (80%) with some Man alpha 1-2Man alpha 1- (15%) and Man alpha 1-3Man alpha 1- (5%). The core region of the yeast anchors (ethanolamine-PO4-6Man alpha 1-2Man alpha 1-6Man alpha 1-4GlcNH2 alpha 1-6myo-inositol-1-PO4) is identical to the conserved core region found in glycosylphosphatidylinositol anchors from protozoa and mammals. The lipid moieties of the total yeast glycosylphosphatidylinositol anchors are mainly ceramides, consisting mostly of C18:0 phytosphingosine and C26:0 fatty acid. However, the lipid moiety of the glycosylphosphatidylinositol anchor of the purified ggp125 protein is a lyso- or diacylglycerol, containing C26:0 fatty acids. This suggests that yeast adds different lipid components to the glycosylphosphatidylinositol anchors of different proteins.
authors.affiliation: Institute of Biochemistry, University of Lausanne, Epalinges, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Fankhauser
authors.forename: S W
authors.initials: SW
authors.lastname: Homans
authors.forename: J E
authors.initials: JE
authors.lastname: Thomas-Oates
authors.forename: M J
authors.initials: MJ
authors.lastname: McConville
authors.forename: C
authors.initials: C
authors.lastname: Desponds
authors.forename: A
authors.initials: A
authors.lastname: Conzelmann
authors.forename: M A
authors.initials: MA
authors.lastname: Ferguson
mesh_terms: D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D005656:Fungal Proteins / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D006017:Glycolipids / Q000737:chemistry; D006020:Glycopeptides / Q000737:chemistry; D017261:Glycosylphosphatidylinositols / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000737:chemistry*; D016339:Spectrometry, Mass, Fast Atom Bombardment
chemical_list: D005656:Fungal Proteins; D006017:Glycolipids; D006020:Glycopeptides; D017261:Glycosylphosphatidylinositols; D008055:Lipids