Profiling water concentration across lipid bilayer membranes by hyscore spectroscopy of nitroxides

Abstract

Organization, dynamics, and function of cellular membranes and their components all depend on the presence of water. However, the highly hydrophobic nature of the bilayer core limits the water penetration and is responsible for large gradients in local water concentrations across the bilayer. Previously, several spin labeling magnetic resonance methods including continuous wave EPR, electron spin echo envelope modulation (ESEEM), and Overhauser dynamic nuclear polarization (ODNP), have been successfully applied to profile water concentration across lipid bilayers, but with limitations.