The N-acetyl-d-glucosaminylphosphatidylinositol De-N-acetylase of glycosylphosphatidylinositol biosynthesis is a zinc metalloenzyme

Michael D Urbaniak, Arthur Crossman, Tunhan Chang, Terry K Smith, Daan M F van Aalten, Michael A J Ferguson

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    The de-N-acetylation of N-acetyl-D-glucosaminylphosphatidylinositol (GlcNAc-PI) is the second step of mammalian and trypanosomal glycosylphosphatidylinositol biosynthesis. Glycosylphosphatidylinositol biosynthesis is essential for Trypanosoma brucei, the causative agent of African sleeping sickness, and GlcNAc-PI de-N-acetylase has previously been validated as a drug target. Inhibition of the trypanosome cell-free system and recombinant rat GlcNAc-PI de-N-acetylase by divalent metal cation chelators demonstrates that a tightly bound divalent metal cation is essential for activity. Reconstitution of metal-free GlcNAc-PI de-N-acetylase with divalent metal cations restores activity in the order Zn2+ > Cu2+ > Ni2+ > Co2+ > Mg2+. Site-directed mutagenesis and homology modeling were used to identify active site residues and postulate a mechanism of action. The characterization of GlcNAc-PI de-N-acetylase as a zinc metalloenzyme will facilitate the rational design of anti-protozoan parasite drugs.

    Original languageEnglish
    Pages (from-to)22831-22838
    Number of pages8
    JournalJournal of Biological Chemistry
    Issue number24
    Publication statusPublished - 17 Jun 2005

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