Discovery, characterization and comparison of inhibitors of Bacillus anthracis and Staphylococcus aureus replicative DNA helicases

Bioorg Med Chem. 2009 Jul 1;17(13):4466-76. doi: 10.1016/j.bmc.2009.05.014. Epub 2009 May 12.


Antibacterial compounds with new mechanisms of action are needed for effective therapy against drug-resistant pathogens in the clinic and in biodefense. Screens for inhibitors of the essential replicative helicases of Bacillus anthracis and Staphylococcus aureus yielded 18 confirmed hits (IC(50)25 microM). Several (5 of 18) of the inhibitors were also shown to inhibit DNA replication in permeabilized polA-deficient B. anthracis cells. One of the most potent inhibitors also displayed antibacterial activity (MIC approximately 5 microg/ml against a range of Gram-positive species including bacilli and staphylococci) together with good selectivity for bacterial versus mammalian cells (CC(50)/MIC>16) suitable for further optimization. This compound shares the bicyclic ring of the clinically proven aminocoumarin scaffold, but is not a gyrase inhibitor. It exhibits a mixed mode of helicase inhibition including a component of competitive inhibition with the DNA substrate (K(i)=8 microM) and is rapidly bactericidal at 4 x MIC.

Publication types

  • Comparative Study
  • Research Support, N.I.H., Extramural

MeSH terms

  • Aminocoumarins / chemistry
  • Aminocoumarins / pharmacology*
  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / pharmacology*
  • Bacillus anthracis / drug effects*
  • Bacillus anthracis / physiology
  • Bacteria / drug effects
  • Bacterial Proteins / antagonists & inhibitors*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Base Sequence
  • Cloning, Molecular
  • DNA Helicases / antagonists & inhibitors*
  • DNA Helicases / genetics
  • DNA Helicases / metabolism
  • DNA Replication / drug effects
  • DNA, Bacterial / genetics
  • Microbial Viability / drug effects
  • Molecular Sequence Data
  • Small Molecule Libraries / chemistry
  • Small Molecule Libraries / pharmacology
  • Staphylococcus aureus / drug effects*
  • Staphylococcus aureus / physiology
  • Structure-Activity Relationship


  • Aminocoumarins
  • Anti-Bacterial Agents
  • Bacterial Proteins
  • DNA, Bacterial
  • Small Molecule Libraries
  • DNA Helicases