Solid-State NMR Characterization of Lipid Membranes

Abstract: This thesis deals with the study of lipid bilayer systems by solid-state nuclear magnetic resonance. Two-dimensional 1H-13C separated local field experiments under magic-angle spinning were employed to investigate structural and dynamical modifications of cell membranes, resulting from the addition of compounds with some biological relevance. For further interpretation of the segmental order obtained from the 2D experiments other methods, such as 31P-NMR, 2H-NMR and molecular dynamics simulations, were also employed. The work presented in this thesis can be divided into two parts. The first part refers to the setup of experimental conditions. Heating and hydration effects were addressed in order to define both the temperature of the system as well as the number of water molecules per lipid necessary to fully hydrate the bilayer. Application of this experimental setup to lipid membrane systems with biological relevance constitutes the second part. The interaction of monogalactosyl- diacylglycerol, the most abundant lipid on earth, with dimyristoylphosphatidylcholine, was studied, which resulted in a frustrated bilayer. Furthermore, small molecules of local anesthetics, with focus on lidocaine, were inserted in the model membrane with the purpose of understanding the influence of local anesthetics on lipid bilayers.