Rotational resonance NMR of biological membranes

Rotational resonance (RR) NMR is a magic angle spinning‐based method for measuring internuclear distances through homonuclear dipolar couplings. RR NMR data obtained from crystals of a hydrophobic α‐helical peptide are used to illustrate general experimental considerations in generating RR magnetization exchange curves and in translating the observed exchange rates into internuclear distances. The extension of RR methods to structural studies of membranes is demonstrated by intramolecular measurements within the transmembrane domain of glycophorin A and between 13C‐labeled sites in lipid bilayers.