STRUCTURE DETERMINATION OF PHOSPHOINOSITOL OLIGOSACCHARIDES FROM PARASITIC PROTOZOA USING FAST-ATOM-BOMBARDMENT MASS-SPECTROMETRY

Glycosylphosphatidylinositols (GPIs) are widely distributed membrane c onstituents of protozoa and higher eukaryotes, where they anchor prote ins and other macromolecules to the cell surface. Free glycosylinosito l phospholipids (i.e. not attached to protein or polysaccharide) have also been detected in some parasitic protozoa, and are thought play a role in the interaction of parasite and host. This paper describes the fast atom bombardment mass spectrometry (FABMS) of glycosylinositol p hospholipids from the Trypanosomatid parasites Leptomonas samueli, End otrypanum schaudinni and Leishmania adleri. FABMS in the positive-and negative-ion modes in conjunction with collisional activation permits the rapid determination of the monosaccharide composition, the sequenc e of residues, the branching pattern and the nature and location of no n-carbohydrate substituents. When supplemented by high-field NMR, FABM S provides a highly efficient route to the complete structure elucidat ion of these materials.