Cyclodextrin-scaffolded alamethicin with remarkably efficient membrane permeabilizing properties and membrane current conductance

J Phys Chem B. 2012 Jul 5;116(26):7652-9. doi: 10.1021/jp2098679. Epub 2012 Jun 25.

Abstract

Bacterial resistance to classical antibiotics is a serious medical problem, which continues to grow. Small antimicrobial peptides represent a potential solution and are increasingly being developed as novel therapeutic agents. Many of these peptides owe their antibacterial activity to the formation of trans-membrane ion-channels resulting in cell lysis. However, to further develop the field of peptide antibiotics, a thorough understanding of their mechanism of action is needed. Alamethicin belongs to a class of peptides called peptaibols and represents one of these antimicrobial peptides. To examine the dynamics of assembly and to facilitate a thorough structural evaluation of the alamethicin ion-channels, we have applied click chemistry for the synthesis of templated alamethicin multimers covalently attached to cyclodextrin-scaffolds. Using oriented circular dichroism, calcein release assays, and single-channel current measurements, the α-helices of the templated multimers were demonstrated to insert into lipid bilayers forming highly efficient and remarkably stable ion-channels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alamethicin / chemistry*
  • Alamethicin / pharmacology
  • Anti-Bacterial Agents / chemistry*
  • Anti-Bacterial Agents / pharmacology
  • Antimicrobial Cationic Peptides / chemistry*
  • Antimicrobial Cationic Peptides / pharmacology
  • Cell Membrane Permeability / drug effects*
  • Circular Dichroism
  • Cyclodextrins / chemistry*
  • Cyclodextrins / pharmacology
  • Drug Resistance, Bacterial*
  • Ion Channels / chemistry
  • Lipid Bilayers / chemistry
  • Patch-Clamp Techniques
  • Peptaibols / chemistry
  • Protein Structure, Secondary

Substances

  • Anti-Bacterial Agents
  • Antimicrobial Cationic Peptides
  • Cyclodextrins
  • Ion Channels
  • Lipid Bilayers
  • Peptaibols
  • Alamethicin