Interaction of the Antimicrobial Peptide Aurein 1.2 and Charged Lipid Bilayer

Abstract

Aurein 1.2 is a potent antimicrobial peptide secreted by frog Litoria aurea. As a short membrane-active peptide with only 13 amino acids in sequence, it has been found to be residing on the surface of lipid bilayer and permeabilizing bacterial membranes at high concentration. However, the detail at the molecular level is largely unknown. In this study, we investigated the action of Aurein 1.2 in charged lipid bilayers composed of DMPC/DMPG. Oriented Circular Dichroism results showed that the peptide was on the surface of lipid bilayer regardless of the charged lipid ratio. Only at a very high peptide-to-lipid ratio (~1/10), the peptide became perpendicular to the bilayer, however no pore was detected by neutron in-plane scattering. To further understand how it interacted with charged lipid bilayers, we employed Small Angle Neutron Scattering to probe lipid distribution across bilayer leaflets in lipid vesicles. The results showed that Aurein 1.2 interacted strongly with negatively charged DMPG, causing strong asymmetry in lipid bilayer. At high concentration, while the vesicles were intact, we found additional structure feature on the bilayer. Our study provides a glimpse into how Aurein 1.2 disturbs anionic lipid-containing membranes without pore formation.

Biophysical investigation into the antibacterial action of modelin-5-NH2

“…Neutron diffraction studies have revealed other mechanisms for the lysis of bilayers by horizontally orientated AMPs involving membrane thinning but not leading to pore or channel formation, such as that recently described for aurein 1.2. The binding of the peptide to membranes induced membrane thinning, accompanied by a major redistribution of PG species in the outer leaflet that appeared to promote the formation of complexes between lipid and aurein 1.2 and the compromise of membrane integrity 58 . A further possibility based on the architecture of M5-MH2 may be that the mode of membrane partitioning used by the peptide leads to the use of a tilted-type mechanism.…”

Could Cardiolipin Protect Membranes against the Action of Certain Antimicrobial Peptides? Aurein 1.2, a Case Study

“…This is interesting as although the potential for the binding of the peptide to induce clustering of POPG was not examined in the present study because of statistical limitations, the finding that Phe 3 was preferentially surrounded by POPG is consistent with results from small-angle neutron scattering experiments that suggested that aurein 1.2 caused the redistribution and clustering of DMPG lipids in a DMPG/DMPC lipid bilayer. 20…”

Aggregation and Its Influence on the Bioactivities of a Novel Antimicrobial Peptide, Temporin-PF, and Its Analogues

“…So far, there are more than 1200 AMPs that have been identified through the skin secretions of different species (DRAMP database v2.0) [7]. They have generally been classified as Aurein [8], Dermaseptin [9], Phyllseptin [10], Phylloxin [11], generally been classified as Aurein [8], Dermaseptin [9], Phyllseptin [10], Phylloxin [11], and Medusin [12], which are found in Hylidae tree frogs; Brevinin [13], Esculentin [14], Japonicin [15], Nigrocin [16], Palustrin [17], Ranatuerin [18], Ranacyclin [19], and Temporin [20], which are discovered from Ranidae frogs; Kassinatuerin [21], which is isolated from genus Kassina; and Magainin [22], which is discovered from the genus Xenopus.…”