Glycoinositol phospholipids from Endotrypanum species express epitopes in common with saccharide side chains of the lipophosphoglycan from Leishmania major
We have characterized glycoinositol phospholipids (GIPLs) from three strains of the trypanosomatid parasites Endotrypanum schaudinni and Endotrypanum monterogeii. Methanolysis of the intact GIPLs liberated methyl esters of tetracosanoic acid, docosanoic acid, octadecanoic acid and hexadecanoic acid and C20 and C21 phytosphingosines. Phosphoinositol oligosaccharides were released from the GIPLs by mild base treatment, and their structures were determined by compositional analysis, fast-atom-bombardment MS and NMR spectroscopy. Similar compounds were detected in all three strains, although their relative proportions varied. The predominant components in E. schaudinni strain LV59 and E. monterogeii LV88 were Galpβ1-3Galpβ1-3Manα1-3Manα1-4GlcNα1-6Ins-1-P and Arapβ1-2Galpβ1-3Galpβ1-3Manα1-3Manα1-4GlcNα1-6Ins-1-P, and the major phosphoinositol oligosaccharide in E. schaudinni LV58 was the hybrid-type GIPL Manα1-2(EtNP-6)Manα1-6(Galpβ1-3Manα1-3)Manα1-4GlcNα1-6Ins-1-P (where EtNP is ethanolamine phosphate). Several minor oligosaccharides containing additional galactose and/or arabinose residues were also detected.