CHEMICAL AND BIOORGANIC STUDIES OF VISUAL PIGMENTS

Proposed an external point-charge model to explain the variance in absorption maxima of visual pigments, an issue of prime importance because the variance has a direct bearing to therecognition of color vision, an area in which our knowledge is extremely limited. Our model was proposed on the basis of the maxima of numerous artificial bovine rhodopsins which were prepared from synthetic retinals have specific structures. We will incorporate these various artificial retinals with opsins from sources other than bovine, such as octopus and chicken. A table of absorption maxima and thus give us a clearer picture of the external point-charge model (we have recently proposed a model to rationalize the purple color of purple membrane, the chromophore of which is again all-trans retinal). Emphasis will also be placed on peptide mapping within the binding site via photo-affinity labelling, and in making artificial rhodopsins which could yield structural information on the bleaching intermediates. Efforts will also continue to be directed towards the synthesis of chormophores which theoretically could shift the vision into regions beyond the normal range.