DXP synthase-catalyzed c-n bond formation: Nitroso substrate specificity studies guide selective inhibitor design

Francine Morris, Ryan Vierling, Lauren Boucher, Jürgen Bosch, Caren L Meyers

Research output: Contribution to journalArticle

Abstract

1-Deoxy-D-xylulose 5-phosphate (DXP) synthase catalyzes the first step in the nonmammalian isoprenoid biosynthetic pathway to form DXP from pyruvate and D-glyceraldehyde 3-phosphate (D-GAP) in a thiamin diphosphate-dependent manner. Its unique structure and mechanism distinguish DXP synthase from its homologues and suggest that it should be pursued as an anti-infective drug target. However, few reports describe any development of selective inhibitors of this enzyme. Here, we reveal that DXP synthase catalyzes C-N bond formation and exploit aromatic nitroso substrates as active site probes. Substrate specificity studies reveal a high affinity of DXP synthase for aromatic nitroso substrates compared to the related ThDP-dependent enzyme pyruvate dehydrogenase (PDH). Results from inhibition and mutagenesis studies indicate that nitroso substrates bind to E. coli DXP synthase in a manner distinct from that of D-GAP. Our results suggest that the incorporation of aryl acceptor substrate mimics into unnatural bisubstrate analogues will impart selectivity to DXP synthase inhibitors. As a proof of concept, we show selective inhibition of DXP synthase by benzylacetylphosphonate (BnAP).

Original languageEnglish (US)
Pages (from-to)1309-1315
Number of pages7
JournalChemBioChem
Volume14
Issue number11
DOIs
Publication statusPublished - Jul 2013

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Keywords

  • Biosynthesis
  • DXP synthase
  • Enzyme inhibitors
  • Isoprenoids
  • Kinetics
  • Substrate specificity

ASJC Scopus subject areas

  • Biochemistry
  • Organic Chemistry
  • Molecular Medicine
  • Molecular Biology

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