CARBOHYDRATE MOIETY OF PLASMODIUM-FALCIPARUM

Malaria is widespread disease and its pathological consequences are due to the development and proliferation of erythrocytic stages in the host. Metabolic labeling of the Plasmodium falciparum parasites with [H-3]-glucosamine, [H-3]-galactose and [H-3]-mannose and subsequent purification in gel filteration or SDS-PAGE yielded labeled glycoproteins. Reductive -elimination of the glycoproteins released molecules containing labeled sugars. Processing of the reaction products and acid hydrolysis of the derived sugars followed by paper chromatography suggested the presence of N-acetylglucosaminitol, N-acetylgalactosaminitol, N-acetylglucosamine and galactose. Following reductive beta-elimination with NaOH-NaBH4 and acid hydrolysis, the products in paper chromatography showed the presence of labeled components that migrated with standard N- acetylglucosaminitol and serine. Enzymes treatment with hexosaminidase and subsequent paper chromatography suggested the release of N-acetylglucosamine. It is unknown at this stage, whether other glycoproteins of P. falciparum have similar types of glycoproteins or bear different types of linkages between the carbohydrate moiety and the protein core. This study represents the first direct investigation into the composition and structure of P. falciparum glycoprotein. In addition we have demonstrated the existence of terminal O- linked GlcNAc in the parasitic glycoprotein.