title: Antimicrobial 14-helical beta-peptides: potent bilayer disrupting agents.
abstract: The interactions of two amphiphilic and cationic, nine-residue beta-peptides with liposomal membranes were studied. These beta-peptides are shown to form 14-helices in the presence of bilayers. Membrane binding and membrane permeabilization occur preferentially in the presence of anionic lipids. The beta-peptides have the ability to cause tranbilayer diffusion of phospholipids, form pores, and promote lipid mixing between liposomes. These beta-peptides have previously been shown to display antimicrobial activity comparable to that of a longer beta-peptide, beta-17, which adopts a different type of helical conformation (12-helix), and to the 23 amino acid (Ala(8,13,18))-magainin-II-amide, which adopts an alpha-helical conformation. In addition, these 14-helical beta-peptides show relatively low hemolytic activity. The biological potency and microbial specificity of the 14-helical beta-peptides, despite their relatively short length, suggests that 14-helices can be particularly disruptive to microbial membranes.
authors.affiliation: Department of Biochemistry, McMaster University Health Sciences Centre, Hamilton, ON, L8N 3Z5 Canada. epand@mcmaster.ca
authors.forename: Raquel F
authors.initials: RF
authors.lastname: Epand
authors.forename: Tami L
authors.initials: TL
authors.lastname: Raguse
authors.forename: Samuel H
authors.initials: SH
authors.lastname: Gellman
authors.forename: Richard M
authors.initials: RM
authors.lastname: Epand
mesh_terms: D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology*; D002152:Calorimetry, Differential Scanning; D002942:Circular Dichroism; D008051:Lipid Bilayers; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid
chemical_list: D000890:Anti-Infective Agents; D008051:Lipid Bilayers