Role of cell surface carbohydrates in malaria

Abstract

Metabolic labelling of Plasmodium falciparum malarial parasites with [3H]-glucosamine, [3H]-galactose, [3H]-mannose, [3H]-ethanolamine and [3H]-myristic acid and subsequent purification in SDS-PAGE yielded, amongst other proteins, the 195 KDa glycoprotein, which is the major merozoite surface antigen. Reductive ß-elimination of the glycoprotein in the gel released labelled sugars. Processing of the reaction products and acid hydrolysis of the derived sugars suggested the presence of N-acetylglucosaminitol, N-acetylglucosamine and other components. Acid hydrolysis of the labelled glycoprotein and examination of the products by chromatography indicated the presence of glucosamine, galactose, mannose, ethanolamine and myristic acid. The 195 KDa glycoprotein was adsorbed by wheat germ agglutinin and desorbed with N-acetylglucosamine. Labelled galactose was incorporated in the glycoprotein by treatment with [3H]-UDP-galactose and bovine milk galactosyl tranferase. The externally glycosylated glycoprotein released labelled galactose on treatment with ß-galactosidase. The carbohydrate chains in the 195 KDa glycoprotein are linked to the protein core through O-glycosyl linkage and N-acetylglucosamine and serine residues are involved in the linkage region. © 1994 IUPAC