Magnetically Aligned Membrane Model Systems with Positive Order Parameter: Switching the Sign of S_(zz) with Paramagnetic Ions

摘要

NMR studies .of biological membrane constituents have traditionally been carried out on samples of multilamellar phospholipid assemblies, suspensions of unilamellar vesicles, or detergent micelles. The use of multilamellar bilayer vesicles is hamperedby the usual solid-state NMR problems: very broad spectra and concomitant poor signal-to-noise and the need for magic angle spinning techniques or specific isotopic labeling. Unilamellar vesicles can be used for high-resolution studies, but short T_2'slimit their utility, and the use of detergent micelles inevitably raises the question about matrix curvature and the biological relevance of detergents.