The hybrid solution/solid-state NMR method for membrane protein structure determination

This chapter describes a hybrid nuclear magnetic resonance (NMR) method for the structure determination of membrane proteins. The method consists in combining distance and orientational restraints derived from both solution and solid-state NMR techniques into a hybrid energy function that is minimized using simulated annealing calculations. Using this approach, we are able to determine the structural ensemble, topological orientation, and depth of insertion of membrane proteins in lipid environments. The feasibility of this method is demonstrated for three different single-pass membrane proteins ranging from 3 to 30. kDa in molecular weight. Finally, this chapter provides an overview of the most recent NMR pulse sequences with enhanced sensitivity and resolution that, along with the hybrid method, will extend the spectroscopy of oriented solid-state NMR to larger membrane protein systems.