GroEL/ES inhibitors as potential antibiotics

Bioorg Med Chem Lett. 2016 Jul 1;26(13):3127-3134. doi: 10.1016/j.bmcl.2016.04.089. Epub 2016 May 4.


We recently reported results from a high-throughput screening effort that identified 235 inhibitors of the Escherichia coli GroEL/ES chaperonin system [Bioorg. Med. Chem. Lett.2014, 24, 786]. As the GroEL/ES chaperonin system is essential for growth under all conditions, we reasoned that targeting GroEL/ES with small molecule inhibitors could be a viable antibacterial strategy. Extending from our initial screen, we report here the antibacterial activities of 22 GroEL/ES inhibitors against a panel of Gram-positive and Gram-negative bacteria, including E. coli, Bacillus subtilis, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter cloacae. GroEL/ES inhibitors were more effective at blocking the proliferation of Gram-positive bacteria, in particular S. aureus, where lead compounds exhibited antibiotic effects from the low-μM to mid-nM range. While several compounds inhibited the human HSP60/10 refolding cycle, some were able to selectively target the bacterial GroEL/ES system. Despite inhibiting HSP60/10, many compounds exhibited low to no cytotoxicity against human liver and kidney cell lines. Two lead candidates emerged from the panel, compounds 8 and 18, that exhibit >50-fold selectivity for inhibiting S. aureus growth compared to liver or kidney cell cytotoxicity. Compounds 8 and 18 inhibited drug-sensitive and methicillin-resistant S. aureus strains with potencies comparable to vancomycin, daptomycin, and streptomycin, and are promising candidates to explore for validating the GroEL/ES chaperonin system as a viable antibiotic target.

Keywords: Antibiotics; Chaperonin; ESKAPE pathogens; GroEL; GroES; HSP10; HSP60; Molecular chaperone; Proteostasis; Small molecule inhibitors.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / chemical synthesis
  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / pharmacology*
  • Cell Line
  • Chaperonin 10 / antagonists & inhibitors*
  • Chaperonin 10 / metabolism
  • Chaperonin 60 / antagonists & inhibitors*
  • Chaperonin 60 / metabolism
  • Dose-Response Relationship, Drug
  • Enzyme Inhibitors / chemical synthesis
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / pharmacology*
  • Gram-Negative Bacteria / drug effects*
  • Gram-Negative Bacteria / enzymology
  • Gram-Positive Bacteria / drug effects*
  • Humans
  • Microbial Sensitivity Tests
  • Molecular Structure
  • Structure-Activity Relationship


  • Anti-Bacterial Agents
  • Chaperonin 10
  • Chaperonin 60
  • Enzyme Inhibitors