RESUMO
Fast atom bombardment mass spectrometry (FAB MS) enables the rapid, accurate and sensitive determination of the molecular masses of glycosylphosphatidylinositol(GPI)-derived oligosaccharides, from which the composition in terms of monosaccharide residues and non-carbohydrate substituents can be determined. Interpretation of fragment ions in collisional activation mass spectra further enables the determination of residue sequence, the positions of branch points, and the location of non-carbohydrate substituents. We have applied these techniques to the characterization of phosphoinositol oligosaccharides from Leptomonas samueli, Endotrypanum schaudinni and Leishmania adleri. The mass spectral data permit the postulation of candidate structures for the oligosaccharides, which provide a set of constraints that can assist the interpretation of results from other techniques such as NMR
Assuntos
Fosfatidilinositóis/química , Glicolipídeos/química , Oligossacarídeos/química , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Trypanosomatina/química , Sequência de Carboidratos , Dados de Sequência MolecularRESUMO
Glycoinositolphospholipids (GIPLs) were extracted from the trypanosomatid Leishmania adleri by hot phenol extraction and the carbohydrate moieties isolated after base cleavage. Purification of the crude oligosaccharides by high performance anion exchange (HPAE) chromatography yielded four fractions whose structures were determined by a combination of methylation analysis, fast atom bombardment (FAB) mass spectrometry and two-dimensional nuclear magnetic resonance (NMR) spectroscopy
Assuntos
Animais , Glicoesfingolipídeos/química , Oligossacarídeos/química , Espectrometria de Massas de Bombardeamento Rápido de Átomos , Trypanosomatina/química , Sequência de Carboidratos , Glicoesfingolipídeos/isolamento & purificação , Dados de Sequência Molecular , Oligossacarídeos/isolamento & purificação , Espectroscopia de Ressonância MagnéticaRESUMO
Nuclear magnetic resonance (NMR) spectroscopy provides an extremely powerful technique to determine the structure of oligosaccharides, particularly when used in conjuction with other physical techniques such as methylation analysis and fast atom bombardment mass spectroscopy (FAB-MS). This brief review describes the application of NMR to the determination of the structure of an oligosaccharide isolated from the glycophosphosphingolipid (GPS) from the monogenetic trypanosomatid Leptomonas samueli. Where ambiguities arise in the NMR interpretation, the use of other data will be discussed