Enamide Prodrugs of Acetyl Phosphonate Deoxy-d-xylulose-5-phosphate Synthase Inhibitors as Potent Antibacterial Agents

ACS Infect Dis. 2019 Mar 8;5(3):406-417. doi: 10.1021/acsinfecdis.8b00307. Epub 2019 Jan 18.


To fight the growing threat of antibiotic resistance, new antibiotics are required that target essential bacterial processes other than protein, DNA/RNA, and cell wall synthesis, which constitute the majority of currently used antibiotics. 1-Deoxy-d-xylulose-5-phosphate (DXP) synthase is a vital enzyme in bacterial central metabolism, feeding into the de novo synthesis of thiamine diphosphate, pyridoxal phosphate, and essential isoprenoid precursors isopentenyl diphosphate and dimethylallyl diphosphate. While potent and selective inhibitors of DXP synthase in vitro activity have been discovered, their antibacterial activity is modest. To improve the antibacterial activity of selective alkyl acetylphosphonate (alkylAP) inhibitors of DXP synthase, we synthesized peptidic enamide prodrugs of alkylAPs inspired by the natural product dehydrophos, a prodrug of methyl acetylphosphonate. This prodrug strategy achieves dramatic increases in activity against Gram-negative pathogens for two alkylAPs, butyl acetylphosphonate and homopropargyl acetylphosphonate, decreasing minimum inhibitory concentrations against Escherichia coli by 33- and nearly 2000-fold, respectively. Antimicrobial studies and LC-MS/MS analysis of alkylAP-treated E. coli establish that the increased potency of prodrugs is due to increased accumulation of alkylAP inhibitors of DXP synthase via transport of the prodrug through the OppA peptide permease and subsequent amide hydrolysis. This work demonstrates the promise of targeting DXP synthase for the development of novel antibacterial agents.

Keywords: 1-deoxy-d-xylulose-5-phosphate synthase; OppA peptide permease; bacterial central metabolism; bacterial metabolic branch point; dehydrophos; phosphonate prodrug.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Anti-Bacterial Agents / chemistry*
  • Anti-Bacterial Agents / pharmacology
  • Enzyme Inhibitors / chemistry*
  • Enzyme Inhibitors / pharmacology
  • Escherichia coli / drug effects*
  • Escherichia coli / enzymology
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / antagonists & inhibitors*
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / metabolism
  • Microbial Sensitivity Tests
  • Pentosephosphates / metabolism
  • Prodrugs / chemistry*
  • Prodrugs / pharmacology
  • Transferases / antagonists & inhibitors*
  • Transferases / chemistry
  • Transferases / metabolism


  • Anti-Bacterial Agents
  • Enzyme Inhibitors
  • Escherichia coli Proteins
  • Pentosephosphates
  • Prodrugs
  • xylulose-5-phosphate
  • Transferases
  • deoxyxylulose-5-phosphate synthase