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THE GECKO OPSIN: RESPONSES TO GEOMETRIC ISOMERS OF RETINAL and 3‐DEHYDRORETINAL
Author(s) -
Crescitelli Frederick,
Liu R. S. H.
Publication year - 1985
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1985.tb03490.x
Subject(s) - photopigment , opsin , pigment , rhodopsin , chemistry , retinal , cis–trans isomerism , gecko , stereochemistry , biology , biochemistry , zoology , organic chemistry
— The opsin of the visual pigment (P521) of the Tokay gecko rapidly regenerates four spectrally different photopigments with the 9‐cis and 11‐cis isomers of both the vitamin A,‐ and A 2 ‐aldehydes. The opsin displays the classic stereospecificity for both A 1 ‐ and A 2 ‐series of isomers. The two photopigments regenerated with 9‐cis‐ and ll‐cw‐3‐dehydroretinals respond to chloride and nitrate ions as do the comparable pigments formed with 9‐cis‐ and 11‐ris‐retinal. The result is a family of pigments absorbing with spectral maxima ranging from 464 to 540 nm, a span of some 3000 cm ‐1 . The photosensitivity of all four pigments was determined and found to be in relative order: 100% (11‐cis‐A 2 ), 77% (11‐ cis ‐A 2 ), 36% (9‐ cis ‐A,) and 14% (9‐ cis ‐A 2 ).