The impact of membrane lipid composition on antimicrobial function of an α-helical peptide

Dennison, Sarah Rachel orcid iconORCID: 0000-0003-4863-9607, Morton, Leslie Hugh Glyn, Harris, Frederick and Phoenix, David Andrew (2008) The impact of membrane lipid composition on antimicrobial function of an α-helical peptide. Chemistry and Physics of Lipids, 151 (2). pp. 92-102. ISSN 00093084

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Official URL: http://dx.doi.org/10.1016/j.chemphyslip.2007.10.00...

Abstract

VP1, a putative α-helical antimicrobial peptide (α-AMP) inhibited growth of Bacillus subtilis and Escherichia coli at 500 μM. The peptide induced stable surface pressure changes in monolayers formed from B. subtilis native lipid extract (circa 4.5 mN m-1) but transient pressure changes in corresponding E. coli monolayers (circa 1.0 mN m-1), which led to monolayer disintegration. Synthetic lipid monolayers mimetic of the extracts were used to generate compression isotherms. Thermodynamic analysis of B. subtilis isotherms indicated membrane stabilisation by VP1 (ΔGMix < 0), via a mechanism dependent upon the phosphatidylglycerol to cardiolipin ratio. Corresponding analysis of E. coli isotherms indicated membrane destabilisation by the peptide (ΔGMix > 0). Destabilisation correlated with PE levels present and appeared to involve a mechanism resembling those used by tilted peptides. These data emphasise that structure / function analysis of α-AMPs must consider not only their structural characteristics but also the lipid make-up of the target microbial membrane.


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