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THE ‘OPSIN SHIFT’ IN BACTERIORHODOPSIN: STUDIES WITH ARTIFICIAL BACTERIORHODOPSINS
Author(s) -
BaloghNair Valeria,
Carriker John D.,
Honig Barry,
Kamat Vinayak,
Motto Michael G.,
Nakanishi Koji,
Sen Ranjan,
Sheves Mordechai,
Tanis Maria Arnaboldi,
Tsujimoto Kazuo
Publication year - 1981
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.1751-1097.1981.tb05449.x
Subject(s) - bacteriorhodopsin , rhodopsin , opsin , chromophore , chemistry , retinal , schiff base , visual pigments , photochemistry , halobacteriaceae , absorption (acoustics) , protonation , pigment , photoprotein , photochromism , crystallography , biophysics , ion , optics , biology , biochemistry , physics , organic chemistry , membrane , bioluminescence , halobacterium salinarum
— The difference (in cm −1 ) in absorption maxima between the protonated Schiff base of retinals and the pigment derived therefrom has been defined as the opsin shift. It represents the influence of the opsin binding site on the chromophore. The analysis of the opsin shifts of a series of dihydrobacteriorhodopsins has led to the external point‐charge model, which in addition to a counter anion near the Schiff base ammonium, carries another negative charge in the vicinity of the β‐ionone ring. This is in striking contrast to the external point‐charge model proposed earlier for the bovine visual pigment. The absorption maxima of rhodopsins formed from bromo‐ and phenyl retinals support the two models. A retinal carrying a photoaffinity label has yielded a nonbleachable bacteriorhodopsin.