Molecular analysis of a novel family of complex glycoinositolphosphoryl ceramides from Cryptococcus neoformans: structural differences between encapsulated and acapsular yeast forms

Glycobiology. 2002 Jul;12(7):409-20. doi: 10.1093/glycob/cwf053.


Complex glycoinositolphosphoryl ceramides (GIPCs) have been purified from a pathogenic encapsulated wild-type (WT) strain of Cryptococcus neoformans var. neoformans and from an acapsular mutant (Cap67). The structures of the GIPCs were determined by a combination of tandem mass spectrometry, nuclear magnetic resonance spectroscopy, methylation analysis, gas chromatography-mass spectrometry, and chemical degradation. The main GIPC from the WT strain had the structure Manp(alpha1-3)[Xylp(beta1-2)] Manp(alpha1-4)Galp(beta1-6)Manp(alpha1-2)Ins-1-phosphoryl ceramide (GIPC A), whereas the compounds from the acapsular mutant were more heterogeneous in their glycan chains, and variants with Manp(alpha1-6) (GIPC B), Manp(alpha1-6) Manp(alpha1-6) (GIPC C), and Manp(alpha1-2)Manp(alpha1-6)Manp(alpha1-6) (GIPC D) substituents linked to the nonreducing terminal mannose residue found in the WT GIPC A were abundant. The ceramide moieties of C. neoformans GIPCs were composed of a C(18) phytosphingosine long-chain base mainly N-acylated with 2-hydroxy-tetracosanoic acid in the WT GIPC while in the acapsular Cap67 mutant GIPCs, as well as 2-hydroxy-tetracosanoic acid, the unusual 2,3-dihydroxy-tetracosanoic acid was characterized. In addition, structural analysis revealed that the amount of GIPC in the WT cells was fourfold less of that in the acapsular mutant.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbohydrate Conformation
  • Carbohydrate Sequence
  • Ceramides / chemistry
  • Ceramides / metabolism*
  • Chromatography, Thin Layer
  • Cryptococcus neoformans / metabolism*
  • Methylation
  • Molecular Sequence Data
  • Nuclear Magnetic Resonance, Biomolecular
  • Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization


  • Ceramides