Our laboratory studies the structural and functional relationship of G protein-coupled receptors with particular focus on the subgroup of receptors known as visual pigments. These pigments, called rhodopins, are major components of rod and cone photoreceptor cells and form the basis of photo-transduction in the vertebrate retina. All rhodopsins are integral membrane proteins, a feature that is typical of G protein-coupled receptors, with seven transmembrane helical segments. What is atypical, however, is that each pigment is covalently bound to an organic chromophore, 11-cis retinal. A ribbon diagram of bovine rhodopsin (PDB:1UI9), with select residues highlighted, is shown in the image on the right. Rho_ribbon