Antibacterial FabH Inhibitors with Mode of Action Validated in Haemophilus influenzae by in Vitro Resistance Mutation Mapping

ACS Infect Dis. 2016 Jul 8;2(7):456-64. doi: 10.1021/acsinfecdis.6b00053. Epub 2016 May 9.

Abstract

Fatty acid biosynthesis is essential to bacterial growth in Gram-negative pathogens. Several small molecules identified through a combination of high-throughput and fragment screening were cocrystallized with FabH (β-ketoacyl-acyl carrier protein synthase III) from Escherichia coli and Streptococcus pneumoniae. Structure-based drug design was used to merge several scaffolds to provide a new class of inhibitors. After optimization for Gram-negative enzyme inhibitory potency, several compounds demonstrated antimicrobial activity against an efflux-negative strain of Haemophilus influenzae. Mutants resistant to these compounds had mutations in the FabH gene near the catalytic triad, validating FabH as a target for antimicrobial drug discovery.

Keywords: FabH; FasII; antibacterial; fatty acid biosynthesis; structure-based drug design; β-ketoacyl-acyl carrier protein synthase III.

MeSH terms

  • 3-Oxoacyl-(Acyl-Carrier-Protein) Synthase / antagonists & inhibitors*
  • 3-Oxoacyl-(Acyl-Carrier-Protein) Synthase / chemistry
  • 3-Oxoacyl-(Acyl-Carrier-Protein) Synthase / genetics
  • 3-Oxoacyl-(Acyl-Carrier-Protein) Synthase / metabolism
  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / pharmacology*
  • Bacterial Proteins / antagonists & inhibitors*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Drug Design
  • Drug Resistance, Bacterial*
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology*
  • Haemophilus Infections / microbiology
  • Haemophilus influenzae / chemistry
  • Haemophilus influenzae / drug effects
  • Haemophilus influenzae / enzymology*
  • Haemophilus influenzae / genetics
  • Humans
  • Microbial Sensitivity Tests
  • Mutation

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Enzyme Inhibitors
  • 3-ketoacyl-acyl carrier protein synthase III
  • 3-Oxoacyl-(Acyl-Carrier-Protein) Synthase