Abstract
We report on the response of asymmetric lipid membranes composed of palmitoyl oleoyl phosphatidylethanolamine and palmitoyl oleoyl phosphatidylglycerol, to interactions with the frog peptides L18W-PGLa and magainin 2 (MG2a), as well as the lactoferricin derivative LF11-215. In particular we determined the peptide-induced lipid flip-flop, as well as membrane partitioning of L18W-PGLa and LF11-215, and vesicle dye-leakage induced by L18W-PGLa. The ability of L18W-PGLa and MG2a to translocate through the membrane appears to correlate with the observed lipid flip-flop, which occurred at the fastest rate for L18W-PGLa. The higher structural flexibility of LF11-215 in turn allows this peptide to insert into the bilayers without detectable changes of membrane asymmetry. The increased vulnerability of asymmetric membranes to L18W-PGLa in terms of permeability, appears to be a consequence of tension differences between the compositionally distinct leaflets, but not due to increased peptide partitioning.
Highlights
Antimicrobial peptides (AMPs) are widely studied compounds of the innate immune system with high potential to combat the spread of infectious diseases due to multi-resistant strains.[1,2] Compared to conventional antibiotics, AMPs translocate or impair cellular envelopes via unspeci c molecular interactions, their nal target might be located in the cytosolic compartment.[3]
We report on the response of asymmetric lipid membranes composed of palmitoyl oleoyl phosphatidylethanolamine and palmitoyl oleoyl phosphatidylglycerol, to interactions with the frog peptides L18W-PGLa and magainin 2 (MG2a), as well as the lactoferricin derivative LF11-215
Various models have been reported for AMP/lipid interactions, including the formation of transmembrane peptide pores, micellization, or interfacial activity, the latter of which may lead to the formation of a surface-adsorbed peptide layer or peptide selfaUniversity of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria
Summary
Antimicrobial peptides (AMPs) are widely studied compounds of the innate immune system with high potential to combat the spread of infectious diseases due to multi-resistant strains.[1,2] Compared to conventional antibiotics, AMPs translocate or impair cellular envelopes via unspeci c molecular interactions (electrostatic, hydrophobic, entropic), their nal target might be located in the cytosolic compartment.[3] Various models have been reported for AMP/lipid interactions, including the formation of transmembrane peptide pores, micellization, or interfacial activity, the latter of which may lead to the formation of a surface-adsorbed peptide layer (carpet) or peptide selfaUniversity of Graz, Institute of Molecular Biosciences, NAWI Graz, 8010 Graz, Austria. Paper aggregation.[4,5,6] Peptide pore formation has been connected to accelerated lipid ip- op,[7,8,9] and recently con rmed for asymmetric lipid membranes.[10,11,12]
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