Membrane binding and permeation by indolicidin analogs studied by a biomimetic lipid/polydiacetylene vesicle assay

Revital Halevy, Annett Rozek, Sofiya Kolusheva, Robert E.W. Hancock, Raz Jelinek

Research output: Contribution to journalArticlepeer-review

52 Scopus citations

Abstract

Membrane binding and relative penetration of indolicidin analogs were studied using lipid/polydiacetylene (PDA) chromatic biomimetic membranes. Colorimetric and fluorescence analyses determined that an indolicidin analog with a proline and tryptophan residue substituted with lysines showed more pronounced bilayer surface interactions, while indolicidin and particularly an indolicidin analog in which all prolines were replaced with alanine residues exhibited deeper insertion into the lipid bilayer. The colorimetric data demonstrated that more pronounced blue-red transitions were observed when the chromatic vesicles incorporated lipopolysaccharide (LPS) within the lipid bilayer, indicating that LPS promoted preferred binding and incorporation of the peptides at the lipid/water interface. The fluorescence quenching experiments further confirmed this outcome. The results indicate that the antibacterial activity of indolicidin most likely requires initial binding to the LPS moieties within bacterial membranes, as well as disruption of the bilayer interface. The degree of hemolysis induced by the analogs, on the other hand, correlated to the extent of penetration into the hydrophobic core of the lipid assembly.

Original languageEnglish
Pages (from-to)1753-1761
Number of pages9
JournalPeptides
Volume24
Issue number11
DOIs
StatePublished - 1 Jan 2003

Keywords

  • Antimicrobial peptides
  • Colorimetric assays
  • Dansyl-PMBN
  • Fluorescence quenching
  • Indolicidin
  • Membranes
  • NBD
  • Polydiacetylene

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Endocrinology
  • Cellular and Molecular Neuroscience

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