Wavelength regulation in iodopsin, a cone pigment

• Published in: Biophysical journal Vol. 55; no. 4; pp. 725 - 729
• Main Authors: Chen, J.G., Nakamura, T., Ebrey, T.G., Ok, H., Konno, K., Derguini, F., Nakanishi, K., Honig, B.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.04.1989
• Subjects: Animals; Chickens; Eye Proteins - physiology; Photoreceptor Cells - physiology; Retinal Pigments - physiology; Rhodopsin - physiology; Rod Opsins; Spectrophotometry; Structure-Activity Relationship
• ISSN: 0006-3495; 1542-0086
• DOI: 10.1016/S0006-3495(89)82871-1

The opsin shift, the difference in wavenumber between the absorption peak of a visual pigment and the protonated Schiff base of the chromophore, represents the influence of the opsin binding site on the chromophore. The opsin shift for the chicken cone pigment iodopsin is much larger than that for rhodopsin. To understand the origin of this opsin shift and the mechanism of wavelength regulation in iodopsin, a series of synthetic 9-cis and 11-cis dehydro- and dihydro-retinals was used to regenerate iodopsin-based pigments. The opsin shifts of these pigments are quite similar to those found in bacteriorhodopsin-based artificial pigments. On the basis of these studies, a tentative model of wavelength regulation in iodopsin is proposed.