A Novel Allosteric Inhibitor of the Uridine Diphosphate N-Acetylglucosamine Pyrophosphorylase from Trypanosoma brucei

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• 作者：Michael D. Urbaniak ; Iain T. Collie ; Wenxia Fang ; Tonia Aristotelous ; Susanne Eskilsson ; Olawale G. Raimi ; Justin Harrison ; Iva Hopkins Navratilova ; Julie A. Frearson ; Daan M. F. van Aalten ; Michael A. J. Ferguson
• 刊名：ACS Chemical Biology
• 出版年：2013
• 出版时间：September 20, 2013
• 年：2013
• 卷：8
• 期：9
• 页码：1981-1987
• 全文大小：435K
• 年卷期：v.8,no.9(September 20, 2013)
• ISSN：1554-8937

文摘

Uridine diphosphate N-acetylglucosamine pyrophosphorylase (UAP) catalyzes the final reaction in the biosynthesis of UDP-GlcNAc, an essential metabolite in many organisms including Trypanosoma brucei, the etiological agent of Human African Trypanosomiasis. High-throughput screening of recombinant T. brucei UAP identified a UTP-competitive inhibitor with selectivity over the human counterpart despite the high level of conservation of active site residues. Biophysical characterization of the UAP enzyme kinetics revealed that the human and trypanosome enzymes both display a strictly ordered bi鈥揵i mechanism, but with the order of substrate binding reversed. Structural characterization of the T. brucei UAP鈥搃nhibitor complex revealed that the inhibitor binds at an allosteric site absent in the human homologue that prevents the conformational rearrangement required to bind UTP. The identification of a selective inhibitory allosteric binding site in the parasite enzyme has therapeutic potential.