Inhibition of the GlcNAc transferase of the glycosylphosphatidylinositol anchor biosynthesis in African trypanosomes

Kenneth G. Milne, Michael Ferguson, Wayne J. Masterson

    Research output: Contribution to journalArticle

    31 Citations (Scopus)

    Abstract

    A wide variety of eukaryotic membrane proteins are anchored to the cell surface by a covalent linkage to glycosylphosphatidylinositol. One of the best characterised examples is the variant surface glycoprotein of the protozoan parasite, Trypanosoma brucei. The pathway for the formation of the glycosylphosphatidylinositol precursor has been previously described, with the first step being the transfer of GlcNAc, from UDP-GlcNAc to endogenous phosphatidylinositol to form N-acetyl-glucosaminylphosphatidylinositol [Doering, T. L., Masterson, W. J., Hart, G. W. & Englund, P. T. (1989) J. Biol. Chem. 264, 11168-11173]. Here we report that low concentrations of sulphydryl alkylating reagents irreversibly inhibit this transferase in a trypanosome-derived cell-free system. The site of inactivation by N-ethylmaleimide appears to be at, or close to, the enzyme active site, since incubation of the enzyme preparation with the donor molecule UDP-GlcNAc substantially protects the enzyme from inactivation. The protection appears to be primarily dependent on the nucleotide portion of the molecule, since UMP and UDP can mimic the protection seen with UDP-GlcNAc.

    Original languageEnglish
    Pages (from-to)309-314
    Number of pages6
    JournalEuropean Journal of Biochemistry
    Volume208
    Issue number2
    DOIs
    Publication statusPublished - Sep 1992

    Keywords

    • ACID
    • VARIANT SURFACE GLYCOPROTEIN
    • STRUCTURAL CHARACTERIZATION
    • PHOSPHATIDYLINOSITOL MEMBRANE ANCHORS
    • PRECURSOR
    • PROTEINS
    • GLYCOSYL-PHOSPHATIDYLINOSITOL
    • BRUCEI

    Cite this