Binding Mode Characterization and Early in Vivo Evaluation of Fragment-Like Thiols as Inhibitors of the Virulence Factor LasB from Pseudomonas aeruginosa

ACS Infect Dis. 2018 Jun 8;4(6):988-997. doi: 10.1021/acsinfecdis.8b00010. Epub 2018 Mar 6.


The increasing emergence of antibiotic resistance necessitates the development of anti-infectives with novel modes of action. Targeting bacterial virulence is considered a promising approach to develop novel antibiotics with reduced selection pressure. The extracellular collagenase elastase (LasB) plays a pivotal role in the infection process of Pseudomonas aeruginosa and therefore represents an attractive antivirulence target. Mercaptoacetamide-based thiols have been reported to inhibit LasB as well as collagenases from clostridia and bacillus species. The present work provides an insight into the structure-activity relationship (SAR) of these fragment-like LasB inhibitors, demonstrating an inverse activity profile compared to similar inhibitors of clostridial collagenase H (ColH). An X-ray cocrystal structure is presented, revealing distinct binding of two compounds to the active site of LasB, which unexpectedly maintains an open conformation. We further demonstrate in vivo efficacy in a Galleria mellonella infection model and high selectivity of the LasB inhibitors toward human matrix metalloproteinases (MMPs).

Keywords: Galleria mellonella; LasB; antibiotic resistance; antivirulence agent; binding mode; elastase; selectivity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / chemical synthesis
  • Anti-Bacterial Agents / chemistry*
  • Anti-Bacterial Agents / pharmacology*
  • Bacterial Proteins / antagonists & inhibitors*
  • Bacterial Proteins / chemistry*
  • Binding Sites
  • Cell Line
  • Chromatography, Liquid
  • Drug Evaluation, Preclinical
  • Drug Resistance, Bacterial
  • Humans
  • Mass Spectrometry
  • Metalloendopeptidases / antagonists & inhibitors*
  • Metalloendopeptidases / chemistry*
  • Models, Molecular
  • Molecular Conformation
  • Molecular Structure
  • Moths / microbiology
  • Protein Binding
  • Pseudomonas aeruginosa / drug effects*
  • Pseudomonas aeruginosa / pathogenicity
  • Pseudomonas aeruginosa / physiology
  • Structure-Activity Relationship
  • Sulfhydryl Compounds / chemical synthesis
  • Sulfhydryl Compounds / chemistry*
  • Sulfhydryl Compounds / pharmacology*
  • Virulence Factors


  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Sulfhydryl Compounds
  • Virulence Factors
  • Metalloendopeptidases
  • pseudolysin, Pseudomonas aeruginosa