Real-time measurement of membrane conformational states induced by antimicrobial peptides: balance between recovery and lysis

Kristopher N Hall, John [Tzong-Hsien] Lee, Adam Istvan Mechler, Marcus J Swann, M-I [Mibel] Aguilar

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Abstract

The disruption of membranes by antimicrobial peptides is a multi-state process involving significant structural changes in the phospholipid bilayer. However, direct measurement of these membrane structural changes is lacking. We used a combination of dual polarisation interferometry (DPI), surface plasmon resonance spectroscopy (SPR) and atomic force microscopy (AFM) to measure the real-time changes in membrane structure through the measurement of birefringence during the binding of magainin 2 (Mag2) and a highly potent analogue in which Ser(8), Gly(13) and Gly(18) has been replaced with alanine (Mag-A). We show that the membrane bilayer undergoes a series of structural changes upon peptide binding before a critical threshold concentration is reached which triggers a significant membrane disturbance. We also propose a detailed model for antimicrobial peptide action as a function of the degree of bilayer disruption to provide an unprecedented in-depth understanding of the membrane lysis in terms of the interconversion of different membrane conformational states in which there is a balance between recovery and lysis.
Original languageEnglish
Pages (from-to)1 - 9
Number of pages9
JournalScientific Reports
Volume4
Issue number(Art. No.:5479)
DOIs
Publication statusPublished - 2014

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