Solid-State NMR Approaches to Study Protein Structure and Protein-Lipid Interactions

Solid-state NMR spectroscopy has been developed for the investigation of membrane-associated polypeptides and remains one of the few techniques to reveal high-resolution structural information in liquid-disordered phospholipid bilayers. While magic angle spinning solid-state NMR remains a popular approach yielding spectra that resemble those in solution, the investigation of static, uniaxially oriented samples provides an alternative concept that has been used to investigate the structure, dynamics, and topology of membrane polypeptides. Much of the previous solid-state NMR work has been developed and performed on peptides, but the technique is constantly expanding toward larger membrane proteins. Here, a number of protocols are presented describing, among others, the reconstitution of membrane proteins into oriented membranes, monitoring membrane alignment by ³¹P solid-state NMR spectroscopy, investigations of the protein by one- and two-dimensional ¹⁵N solid-state NMR and measurements of the lipid order parameters using ²H solid-state NMR spectroscopy. Using such methods, solid-state NMR spectroscopy has revealed a detailed picture of the ensemble of both lipids and proteins and their mutual interdependence in the bilayer environment.