We are proposing the study of an important transmembrane protein Rhodopsin. This protein is composed of a seven helix transmembrane part (a member of the G-Protein Coupled Receptor family) which possesses the retinylidene chromophore in its binding pocket at the center of the protein. The structure of G-proteins are now known to atomic detail, but the structure of their receptors are not. The protein will be studied in its native environment with solid state 2H-NMR spectroscopy. Unlike magic angle spinning NMR spectroscopy, solid state 2H-NMR spectroscopy give orientational information which allows for the determination of both conformation and orientation. Rhodopsin will be regenerated with specifically deuterated 11-cis retinal for 2H-NMR studies of retinal in the ground state and in the meta II state. Together, this information will explain the conformational change that occurs upon photolysis of 11-cis retinal which may eventually lead to the specific mechanism of activation of transducin along the signalling pathway.
