Structural characterization of POPC and C12E4 in their mixed membranes at reduced hydration by solid state 2H NMR

The structural properties of the palmitoyl and dodecyl chains as well as of the headgroups of POPC and C12E4, respectively, were obtained at 25 degrees C in the pure and mixed membranes hydrated at the same relative humidity of 97% by deuterium NMR utilizing partially deuterated lipids and surfactants. Results showed a thickening of the bilayer and its hydrophobic core because of the stretching of the surfactant dodecyl chain which is mainly due to the reduction of the surfactant headgroup repulsions.