The effect of gramicidin inclusions on the local order of membrane components

Elise Azar (1) , Doru Constantin (1) , Dror E. Warschawski (2)

1 LPS - Laboratoire de Physique des Solides
2 LBPC-PM (UMR_7099) - Laboratoire de biologie physico-chimique des protéines membranaires

We study the local effect of the antimicrobial peptide Gramicidin A on bilayers composed of lipids or surfactants using nuclear magnetic resonance spectroscopy and wide-angle X-ray scattering, techniques that probe the orientational and positional order of the alkyl chains, respectively. The two types of order vary with temperature and peptide concentration in complex ways which depend on the membrane composition, highlighting the subtlety of the interaction between inclusions and the host bilayer. The amplitude of the variation is relatively low, indicating that the macroscopic constants used to describe the elasticity of the bilayer are unlikely to change with the addition of peptide.

Mots clés: gramicidin; membranes; NMR; WAXS; order parameter

Domaines: Matière Molle [cond-mat.soft]; Biophysique [physics.bio-ph]

Elise Azar, Doru Constantin, Dror E. Warschawski. The effect of gramicidin inclusions on the local order of membrane components. European Physical Journal E: Soft matter and biological physics, 2018, 41 (3), pp.44. ⟨10.1140/epje/i2018-11644-5⟩. ⟨hal-01744850⟩