Glycosylation reactions in Plasmodium falciparum, Toxoplasma gondii, and Trypanosoma brucei brucei probed by the use of synthetic peptides.
Synthetic peptides were used to probe O- and N-glycosylation reactions in cell-free systems of the parasitic protozoa Plasmodium falciparum, Toxoplasma gondii, and Trypanosoma brucei brucei. O-Glycosylation of the peptide Pro-Tyr-Thr-Val-Val was observed with lysates from all organisms. However, the spectrum of sugars transferred from their respective nucleotide or dolichol-phosphate derivatives to the peptide varied greatly according to the parasite. N-glycosylation of the peptides N-Bz-Asn-Gly-ThrNH2 and DNP-Arg-Asn-Ala-Thr-Ala-ValNH2 by exogenous radioactive dolichol-pyrophosphate linked oligosaccharide donors was observed only when lysates of T. gondii or T. b. brucei were used, but not in P. falciparum. To assay for endogenous N-glycosylation donors, the radiolabeled tripeptide [3H]Ac-Asn-Gly-ThrNHMe was used as acceptor. The peptide was N-glycosylated only by T. gondii and T. b. brucei preparations. Only in these latter two parasites dolichol-cycle mannosyltransferase activity was demonstrated by the elongation of exogenous radiolabeled dolichol-PP-chitobiose. The data substantiate the occurrence of protein O-glycosylation in parasitic protozoa and the exceptional absence of protein N-glycosylation in the asexual intraerythrocytic stage of the malaria parasite, P. falciparum.
Dieckmann-Schuppert
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A
Zentrum für Hygiene und Medizinische Mikrobiologie, Universität Marburg, FRG.
Bause
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E
Schwarz
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RT
D000595:Amino Acid Sequence; D000818:Animals; D002474:Cell-Free System; D002642:Chick Embryo; D004910:Erythrocyte Membrane / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D008862:Microsomes, Liver / Q000378:metabolism; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism*; D010963:Plasmodium falciparum / Q000378:metabolism*; D051381:Rats; D014122:Toxoplasma / Q000378:metabolism*; D014346:Trypanosoma brucei brucei / Q000378:metabolism*
D010455:Peptides