Interaction of antimicrobial peptides from Australian amphibians with lipid membranes

• Published in: Chemistry and physics of lipids 2003, Vol.122 (1), p.107-120
• Main Authors: Marcotte, Isabelle, Wegener, Kate L., Lam, Yuen-Han, Chia, Brian C.S., de Planque, Maurits R.R., Bowie, John H., Auger, Michèle, Separovic, Frances
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amphibians; Animals; Antimicrobial Cationic Peptides - chemistry; Antimicrobial peptides; Circular Dichroism; Lipid Bilayers; Lipid membranes; Lysis; Magnetic Resonance Spectroscopy; Membrane Lipids - chemistry; Molecular Sequence Data; NMR; Phospholipids - chemistry; Protein Conformation; Structure
• ISSN: 0009-3084; 1873-2941
• DOI: 10.1016/S0009-3084(02)00182-2

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 α-helical conformation with helix long axis ∼50° 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.