Determining the mode of action involved in the antimicrobial activity of synthetic peptides: a solid-state NMR and FTIR study.
We have previously shown that leucine to lysine substitution(s) in neutral synthetic crown ether containing 14-mer peptide affect the peptide structure and its ability to permeabilize bilayers. Depending on the substitution position, the peptides adopt mainly either a α-helical structure able to permeabilize dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylglycerol (DMPG) vesicles (nonselective peptides) or an intermolecular β-sheet structure only able to permeabilize DMPG vesicles (selective peptides). In this study, we have used a combination of solid-state NMR and Fourier transform infrared spectroscopy to investigate the effects of nonselective α-helical and selective intermolecular β-sheet peptides on both types of bilayers. (31)P NMR results indicate that both types of peptides interact with the headgroups of DMPC and DMPG bilayers. (2)H NMR and Fourier transform infrared results reveal an ordering of the hydrophobic core of bilayers when leakage is noted, i.e., for DMPG vesicles in the presence of both types of peptides and DMPC vesicles in the presence of nonselective peptides. However, selective peptides have no significant effect on the ordering of DMPC acyl chains. The ability of these 14-mer peptides to permeabilize lipid vesicles therefore appears to be related to their ability to increase the order of the bilayer hydrophobic core.
Département de chimie, PROTEO (Regroupement Québécois de Recherche sur la Fonction, la Structure et l'Ingénierie des Protéines), CERMA (Centre de Recherche sur les Matériaux Avancés), Université Laval, Québec, Québec, Canada.
Aurélien
A
Lorin
Mathieu
M
Noël
Marie-Ève
MÈ
Provencher
Vanessa
V
Turcotte
Sébastien
S
Cardinal
Patrick
P
Lagüe
Normand
N
Voyer
Michèle
M
Auger
D000595:Amino Acid Sequence; D000890:Anti-Infective Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D002462:Cell Membrane / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D004134:Dimyristoylphosphatidylcholine / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D010715:Phosphatidylglycerols / Q000378:metabolism; D017433:Protein Structure, Secondary; D017550:Spectroscopy, Fourier Transform Infrared
D000890:Anti-Infective Agents; D008051:Lipid Bilayers; D010455:Peptides; D010715:Phosphatidylglycerols; C002773:dimyristoylphosphatidylglycerol; D004134:Dimyristoylphosphatidylcholine