Glycosylinositol phospholipid anchors of the scrapie and cellular prion proteins contain sialic acid

Biochemistry. 1992 Jun 2;31(21):5043-53. doi: 10.1021/bi00136a600.


The only identified component of the scrapie prion is PrPSc, a glycosylinositol phospholipid (GPI)-linked protein that is derived from the cellular isoform (PrPC) by an as yet unknown posttranslational event. Analysis of the PrPSc GPI has revealed six different glycoforms, three of which are unprecedented. Two of the glycoforms contain N-acetylneuraminic acid, which has not been previously reported as a component of any GPI. The largest form of the GPI is proposed to have a glycan core consisting of Man alpha-Man alpha-Man-(NeuAc-Gal-GalNAc-)Man-GlcN-Ino. Identical PrPSc GPI structures were found for two distinct isolates or "strains" of prions which specify different incubation times, neuropathology, and PrPSc distribution in brains of Syrian hamsters. Limited analysis of the PrPC GPI reveals that it also has sialylated glycoforms, arguing that the presence of this monosaccharide does not distinguish PrPC from PrPSc.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Carbohydrate Sequence
  • Chromatography, High Pressure Liquid
  • Chromatography, Ion Exchange
  • Electrophoresis, Gel, Two-Dimensional
  • Electrophoresis, Polyacrylamide Gel
  • Glycolipids / chemistry*
  • Glycosylphosphatidylinositols
  • Lectins / metabolism
  • Mannosidases / chemistry
  • Mass Spectrometry / methods
  • Molecular Sequence Data
  • N-Acetylneuraminic Acid
  • Phosphatidylinositols / chemistry*
  • PrPSc Proteins
  • Prions / chemistry*
  • Prions / isolation & purification
  • Sialic Acids / analysis*
  • alpha-Mannosidase


  • Glycolipids
  • Glycosylphosphatidylinositols
  • Lectins
  • Phosphatidylinositols
  • PrPSc Proteins
  • Prions
  • Sialic Acids
  • Mannosidases
  • alpha-Mannosidase
  • N-Acetylneuraminic Acid