Molecular analysis of a novel family of complex glycoinositolphosphoryl ceramides from Cryptococcus neoformans: structural differences between encapsulated and acapsular yeast forms.
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.
Instituto de Biofísica Carlos Chagas Filho, Centro de Ciências da Saúde, Bloco G, Universidade Federal do Rio de Janeiro, 21944-970, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ, Brasil.
Norton
N
Heise
Ana L S
AL
Gutierrez
Katherine A
KA
Mattos
Christopher
C
Jones
Robin
R
Wait
José O
JO
Previato
Lucia
L
Mendonça-Previato
D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002518:Ceramides / Q000737:chemistry / Q000378:metabolism*; D002855:Chromatography, Thin Layer; D003455:Cryptococcus neoformans / Q000378:metabolism*; D008745:Methylation; D008969:Molecular Sequence Data; D019906:Nuclear Magnetic Resonance, Biomolecular; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D002518:Ceramides