About 60% of all current drug targets are G-protein-coupled receptors (GPCRs), yet no complete structure is available for any of these drug targets. The Yeagle lab has developed a novel approach to membrane protein structure in which the structure of the intact protein is assembled from NMR-derived structures of overlapping peptide fragments. The solution structure of rhodopsin determined using this method was very similar to that of the crystal structure but additionally enabled the cytoplasmic face of receptor to be defined for the first time. The figure shows an "ionic lock" on the cytoplasmic face of rhodopsin that stabilizes the ground state of this GPCR.
Yeagle, P.L., Choi, G. and Albert, A.D. (2001) Studies on the structure of the G-protein-coupled receptor rhodopsin including the putative G-protein binding site in unactivated and activated forms. Biochemistry 40, 11932-11937.