Deciphering the Role of Intramolecular Networking in Cholic Acid-Peptide Conjugates on the Lipopolysaccharide Surface in Combating Gram-Negative Bacterial Infections

J Med Chem. 2019 Feb 28;62(4):1875-1886. doi: 10.1021/acs.jmedchem.8b01357. Epub 2019 Feb 11.


The presence of lipopolysaccharide and emergence of drug resistance make the treatment of Gram-negative bacterial infections highly challenging. Herein, we present the synthesis and antibacterial activities of cholic acid-peptide conjugates (CAPs), demonstrating that valine-glycine dipeptide-derived CAP 3 is the most effective antimicrobial. Molecular dynamics simulations and structural analysis revealed that a precise intramolecular network of CAP 3 is maintained in the form of evolving edges, suggesting intramolecular connectivity. Further, we found high conformational rigidity in CAP 3 that confers maximum perturbations in bacterial membranes relative to other small molecules. Interestingly, CAP 3-coated catheters did not allow the formation of biofilms in mice, and treatment of wound infections with CAP 3 was able to clear the bacterial infection. Our results demonstrate that molecular conformation and internal connectivity are critical parameters to describe the antimicrobial nature of compounds, and the analysis presented here may serve as a general principle for the design of future antimicrobials.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acinetobacter baumannii / drug effects
  • Acinetobacter baumannii / metabolism
  • Animals
  • Anti-Bacterial Agents / chemical synthesis
  • Anti-Bacterial Agents / pharmacology
  • Anti-Bacterial Agents / therapeutic use*
  • Biofilms / drug effects
  • Cholic Acids / chemical synthesis
  • Cholic Acids / pharmacology
  • Cholic Acids / therapeutic use*
  • Escherichia coli / drug effects
  • Escherichia coli / metabolism
  • Escherichia coli / physiology
  • Gram-Negative Bacteria / drug effects*
  • Gram-Negative Bacteria / metabolism
  • Gram-Negative Bacteria / physiology
  • Gram-Negative Bacterial Infections / drug therapy*
  • Klebsiella pneumoniae / drug effects
  • Klebsiella pneumoniae / metabolism
  • Lipopolysaccharides / metabolism*
  • Mice, Inbred BALB C
  • Microbial Sensitivity Tests
  • Molecular Conformation
  • Molecular Dynamics Simulation
  • Peptides / chemical synthesis
  • Peptides / pharmacology
  • Peptides / therapeutic use*
  • Structure-Activity Relationship


  • Anti-Bacterial Agents
  • Cholic Acids
  • Lipopolysaccharides
  • Peptides