ABSTRACT
Disruption of glycosylphosphatidylinositol biosynthesis is genetically and chemically validated as a drug target against the protozoan parasite Trypanosoma brucei, the causative agent of African sleeping sickness. The N-acetylglucosamine-phosphatidylinositol de-N-acetylase (deNAc) is a zinc metalloenzyme responsible for the second step of glycosylphosphatidylinositol biosynthesis. We recently reported the synthesis of eight deoxy-2-C-branched monosaccharides containing carboxylic acid, hydroxamic acid, or N-hydroxyurea substituents at the C2 position that may act as zinc-binding groups. Here, we describe the synthesis of a glucocyclitol-phospholipid incorporating a hydroxamic acid moiety and report the biochemical evaluation of the monosaccharides and the glucocyclitol-phospholipid as inhibitors of the trypanosome deNAc in the cell-free system and against recombinant enzyme. Monosaccharides with carboxylic acid or hydroxamic acid substituents were found to be the inhibitors of the trypanosome deNAc with IC(50) values 0.1-1.5mM and the glucocyclitol-phospholipid was found to be a dual inhibitor of the deNAc and the α1-4-mannose transferase with an apparent IC(50)= 19±0.5µm.
Subject(s)
Amidohydrolases/antagonists & inhibitors , Enzyme Inhibitors/pharmacology , Trypanocidal Agents/pharmacology , Trypanosoma brucei brucei/enzymology , Trypanosomiasis, African/parasitology , Zinc/metabolism , Amidohydrolases/genetics , Amidohydrolases/metabolism , Animals , Drug Design , Enzyme Inhibitors/chemistry , Glycosylphosphatidylinositols/biosynthesis , Phospholipids/chemistry , Recombinant Proteins/antagonists & inhibitors , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Trypanocidal Agents/chemistry , Zinc/chemistryABSTRACT
A small zinc-binding group (ZBG) library of deoxy-2-C-branched-monosaccharides, for example, 1,5-anhydroglucitols, consisting of either monodentate ligand binding carboxylic acids or bidentate ligand binding hydroxamic acids, were prepared to assess the zinc affinity of the putative metalloenzyme 2-acetamido-2-deoxy-α-D-glucopyranosyl-(1â6)-phosphatidylinositol de-N-acetylase (EC 3.5.1.89) of glycosylphosphatidylinositol biosynthesis. The N-ureido thioglucoside was also synthesised and added to the ZBG library because a previous N-ureido analogue, synthesised by us, had inhibitory activity against the aforementioned de-N-acetylase, presumably via the N-ureido motif.
Subject(s)
Acetylesterase/antagonists & inhibitors , Acetylesterase/metabolism , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/chemical synthesis , Metalloproteins/metabolism , Trypanosoma brucei brucei/enzymology , Zinc/metabolism , Enzyme Inhibitors/pharmacology , Glycosylphosphatidylinositols/biosynthesis , Magnetic Resonance Spectroscopy , Metalloproteins/antagonists & inhibitors , Molecular StructureABSTRACT
We report the extension of the copper(II) tetrafluoroborate catalysed opening of epoxides with alcohols to include a wider variety of alcohols, a range of solvents and a method to purify the products from the reaction.
ABSTRACT
1-D-6-O-[2-(N-hydroxyaminocarbonyl)amino-2-deoxy-alpha-D-glucopyranosyl]-myo-inositol 1-(n-octadecyl phosphate) was prepared to probe the reaction mechanism of the putative zinc-dependent metalloenzyme 2-acetamido-2-deoxy-alpha-D-glucopyranosyl-(1-->6)-phosphatidylinositol de-N-acetylase of glycosylphosphatidylinositol biosynthesis.