This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. (A) OBJECTIVES Retinal degeneration is a major genetic and age related cause of serious eye disease and blindness. Understanding the molecular interactions of natural and synthetic agonists and antagonists with the visual pigments can provide a new route to halting and possibly reversing such degeneration. This collaboration will utilize grid-enabled AutoLigand and AutoDock, as well as AutoDockTools to computationally, 1) characterize the ligand binding sites of the human rod and cone opsin proteins. 2) predict the binding modes and free energies of known agonists and inverse agonists and 3) explore new inverse agonists using AutoDock Tools interactive Autoligand enhanced interface to help design ligands with increased potency and specificity. The efficacy of the new inverse agonists will be validated using biochemical studies with the human opsin proteins to demonstrate protein ligand interactions.