title: The green-absorbing Drosophila Rh6 visual pigment contains a blue-shifting amino acid substitution that is conserved in vertebrates.
abstract: The molecular mechanisms that regulate invertebrate visual pigment absorption are poorly understood. Through sequence analysis and functional investigation of vertebrate visual pigments, numerous amino acid substitutions important for this adaptive process have been identified. Here we describe a serine/alanine (S/A) substitution in long wavelength-absorbing Drosophila visual pigments that occurs at a site corresponding to Ala-292 in bovine rhodopsin. This S/A substitution accounts for a 10-17-nm absorption shift in visual pigments of this class. Additionally, we demonstrate that substitution of a cysteine at the same site, as occurs in the blue-absorbing Rh5 pigment, accounts for a 4-nm shift. Substitutions at this site are the first spectrally significant amino acid changes to be identified for invertebrate pigments sensitive to visible light and are the first evidence of a conserved tuning mechanism in vertebrate and invertebrate pigments of this class.
authors.affiliation: Department of Cell and Developmental Biology, University of Colorado Denver, Aurora, Colorado 80045, USA.
authors.forename: Ernesto
authors.initials: E
authors.lastname: Salcedo
authors.forename: David M
authors.initials: DM
authors.lastname: Farrell
authors.forename: Lijun
authors.initials: L
authors.lastname: Zheng
authors.forename: Meridee
authors.initials: M
authors.lastname: Phistry
authors.forename: Eve E
authors.initials: EE
authors.lastname: Bagg
authors.forename: Steven G
authors.initials: SG
authors.lastname: Britt
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D030801:Animals, Genetically Modified; D002417:Cattle; D003118:Color Perception; D004331:Drosophila melanogaster / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D008027:Light; D016297:Mutagenesis, Site-Directed; D009154:Mutation / Q000235:genetics; D010802:Phylogeny; D017949:Retinal Cone Photoreceptor Cells; D012168:Retinal Pigments / Q000737:chemistry*; D012243:Rhodopsin / Q000737:chemistry* / Q000502:physiology*
chemical_list: D012168:Retinal Pigments; D012243:Rhodopsin