Lipid bilayers mechanically aligned

Several works have been reported for macroscopically orientated biological membranes.106-109 The biomembrane alignment can be carried out mechanically or magnetically. The first one relies on the deposition of lipid bilayers on the surface of a rigid support (glass plates) such that the bilayer normal is perpendicular to the surface of the support itself. Small peptides and the lipid bilayers can be dissolved in organic solvents which are successively removed under vacuum.105 The re-hydration of the system in a chamber of an optimized temperature, humidity and time gives rise to the desired orientation. 

The use of three-dimensional spectroscopy involving chemical shift/ H- N dipolar coupling/ N chemical shift correlation has been shown to improve spectral resolution in studies of membrane proteins with helices aligned parallel to the membrane surface. Such a measurement on the antibiotic peptide magainin enabled the three-dimensional orientation of this helical peptide to be determined in the lipid bilayer. The orientation of the insect antiobiotic peptide cecropin A in the phospholipid bilayer membrane has been determined using solid-state NMR spectroscopy and the result discussed in relation to the mechanism of action of the peptide. ... 

The transmembrane portion of the M2 protein from the influenza A virus has been studied in hydrated DMPC lipid bilayers with solid-state NMR.209 Orientational constraints are obtained from the isotopically labeled peptide samples mechanically aligned between thin glass plates. I5N chemical shifts from single-site labeled samples constrain the molecular frame with respect to... 

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