Progress of membrane protein structural studies

Membrane proteins play vital roles in maintaining cells proper function, but structural studies of membrane proteins lag far behind water soluble proteins. Because it is unnecessary to prepare crystals of membrane proteins, nuclear magnetic resonance (NMR) is coming to play an increasingly important role in membrane protein structural studies. Several NMR methods can be applied for different states of membrane protein samples. Solution NMR is used to study membrane protein in detergent micelles or in low q bicelles, and several membrane proteins structures have been solved using solution NMR. Static oriented solid state NMR can be applied for uniformly oriented membrane proteins in high q bicelles or in lipid bilayers. Methods of magic angle spinning (MAS) solid state NMR are also under development to solve membrane protein structures in lipid bilayers.