Small Amphiphilic Peptides: Activity Against a Broad Range of Drug-Resistant Bacteria and Structural Insight into Membranolytic Properties

J Med Chem. 2022 Jan 13;65(1):665-687. doi: 10.1021/acs.jmedchem.1c01782. Epub 2022 Jan 3.

Abstract

We report the synthesis and antibacterial activities of a series of amphiphilic membrane-active peptides composed, in part, of various nongenetically coded hydrophobic amino acids. The lead cyclic peptides, 8C and 9C, showed broad-spectrum activity against drug-resistant Gram-positive (minimum inhibitory concentration (MIC) = 1.5-6.2 μg/mL) and Gram-negative (MIC = 12.5-25 μg/mL) bacteria. The cytotoxicity study showed the predominant lethal action of the peptides against bacteria as compared with mammalian cells. A plasma stability study revealed approximately 2-fold higher stability of lead cyclic peptides as compared to their linear counterparts after 24 h of incubation. A calcein dye leakage experiment revealed the membranolytic effect of the cyclic peptides. Nuclear magnetic resonance spectroscopy and molecular dynamics simulation studies of the interaction of the peptides with the phospholipid bilayer provided a solid structural basis to explain the membranolytic action of the peptides with atomistic details. These results highlight the potential of newly designed amphiphilic peptides as the next generation of peptide-based antibiotics.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / chemical synthesis*
  • Anti-Bacterial Agents / pharmacology*
  • Antimicrobial Cationic Peptides
  • Bacteria / drug effects*
  • Cell Membrane / drug effects*
  • Cell Survival / drug effects
  • Drug Design
  • Gram-Negative Bacteria / drug effects
  • Gram-Positive Bacteria / drug effects
  • HEK293 Cells
  • Hemolysis / drug effects
  • Humans
  • Magnetic Resonance Spectroscopy
  • Microbial Sensitivity Tests
  • Molecular Dynamics Simulation
  • Peptides / chemical synthesis*
  • Peptides / pharmacology*

Substances

  • Anti-Bacterial Agents
  • Antimicrobial Cationic Peptides
  • Peptides