Interaction of antimicrobial peptides from Australian amphibians with lipid membranes.
Solid-state NMR and CD spectroscopy were used to study the effect of antimicrobial peptides (aurein 1.2, citropin 1.1, maculatin 1.1 and caerin 1.1) from Australian tree frogs on phospholipid membranes. 31P NMR results revealed some effect on the phospholipid headgroups when the peptides interact with DMPC/DHPC (dimyristoylphosphatidylcholine/dihexanoylphosphatidylcholine) bicelles and aligned DMPC multilayers. 2H NMR showed a small effect of the peptides on the acyl chains of DMPC in bicelles or aligned multilayers, suggesting interaction with the membrane surface for the shorter peptides and partial insertion for the longer peptides. 15N NMR of selectively labelled peptides in aligned membranes and oriented CD spectra indicated an alpha-helical conformation with helix long axis approximately 50 degrees to the bilayer surface at high peptide concentrations. The peptides did not appear to insert deeply into PC membranes, which may explain why these positively charged peptides preferentially lyse bacterial rather than eucaryotic cells.
Marcotte
Isabelle
I
Département de Chimie, Centre de Recherche en Sciences et en Ingénierie des Macromolécules, Université Laval, Québec, Québec, Canada G1K 7P4.
Wegener
Kate L
KL
Lam
Yuen-Han
YH
Chia
Brian C S
BC
de Planque
Maurits R R
MR
Bowie
John H
JH
Auger
Michèle
M
Separovic
Frances
F
D000595:Amino Acid Sequence; D000663:Amphibians; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry*; D002942:Circular Dichroism; D008051:Lipid Bilayers; D009682:Magnetic Resonance Spectroscopy; D008563:Membrane Lipids / Q000737:chemistry*; D008969:Molecular Sequence Data; D010743:Phospholipids / Q000737:chemistry*; D011487:Protein Conformation
D023181:Antimicrobial Cationic Peptides; D008051:Lipid Bilayers; D008563:Membrane Lipids; D010743:Phospholipids