ROLE OF HYDROXYL‐BEARING AMINO ACIDS IN DIFFERENTIALLY TUNING THE ABSORPTION SPECTRA OF THE HUMAN RED AND GREEN CONE PIGMENTS

摘要: The human red and green cone pigments differ at either 15 or 16 amino acids, depending upon which polymorphic variants are compared. Seven of these acid differences involve the introduction removal a hydroxyl group. One differences, substitution alanine for serine position 180, was found previously to produce 5 nm blue shift. To determine role remaining six group in tuning absorption spectra pigments, we have studied site-directed mutants single acids from pigment been substituted corresponding residues pigment. Blue shifts 7 14 were observed phenylalanine tyrosine 277 threonine 285, respectively. Single substitutions positions 65, 230, 233, 309 produced spectral 1 less. These data good agreement with model based sequence comparisons among primate properties bovine rhodopsin. Nonadditive effects comparing red-green hybrid remain be explained.