title: Amino acid replacements and wavelength absorption of visual pigments in vertebrates.
abstract: An important unanswered question in phototransduction is how visual pigments (VPs) regulate their wavelength of maximal absorption (lambda max). By constructing the evolutionary tree for 28 opsins with known lambda max values, we can identify the times and directions of lambda max shift of different VPs. A total of 55 amino acid changes are shown to correlate with the directions of lambda max shift and might have been important in determining lambda max of a VP. Among these, three amino acid changes are already proven to be responsible in modifying the green-sensitive VP to the red-sensitive VP. The present evolutionary analysis opens a new direction in understanding the mechanism for the regulation of wavelength absorption by a VP and, more generally, in studying molecular mechanism involved in adaptive evolution.
authors.affiliation: Department of Biology, Syracuse University, New York 13214.
authors.forename: S
authors.initials: S
authors.lastname: Yokoyama
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D005075:Biological Evolution; D014644:Genetic Variation; D006801:Humans; D008969:Molecular Sequence Data; D017354:Point Mutation; D017433:Protein Structure, Secondary; D012168:Retinal Pigments / Q000737:chemistry / Q000235:genetics*; D017299:Rod Opsins / Q000737:chemistry / Q000235:genetics*; D017386:Sequence Homology, Amino Acid; D013053:Spectrophotometry; D014714:Vertebrates / Q000145:classification / Q000235:genetics*
chemical_list: D012168:Retinal Pigments; D017299:Rod Opsins