This paper is part of the Proceedings of the 12th International Conference on Retinal Proteins held at Awaji Island, Hyogo, Japan on 4–8 June 2006.
Modulation of the Absorption Maximum of Rhodopsin by Amino Acids in the C-terminus†
Article first published online: 28 MAR 2007
Photochemistry and Photobiology
Volume 83, Issue 2, pages 236–241, March/April 2007
How to Cite
Yokoyama, S., Tada, T. and Yamato, T. (2007), Modulation of the Absorption Maximum of Rhodopsin by Amino Acids in the C-terminus. Photochemistry and Photobiology, 83: 236–241. doi: 10.1562/2006-06-19-RA-939
- Issue published online: 28 MAR 2007
- Article first published online: 28 MAR 2007
- Received 19 June 2006; accepted 17 August 2006; published online 21 August 2006; DOI: 10.1562/2006-06-19-RA-939
Vision begins when light is absorbed by visual pigments. It is commonly believed that the absorption spectra of visual pigments are modulated by interactions between the retinal and amino acids within or near 4.5 Å of the retinal in the transmembrane (TM) segments. However, this dogma has not been rigorously tested. In this study, we show that the retinal-opsin interactions extend well beyond the retinal binding pocket. We found that, although it is positioned outside of TM segments, the C-terminus of the rhodopsin in the rockfish longspine thornyhead (Sebastolobus altivelis) modulates its λmax by interacting mainly with the last TM segment. Our results illustrate how amino acids in the C-terminus are likely to interact with the retinal. We anticipate our analyses to be a starting point for viewing the spectral tuning of visual pigments as interactions between the retinal and key amino acids that are distributed throughout the entire pigment.