This paper is part of the Proceedings of the 13th International Conference on Retinal Proteins, Barcelona, Spain, 15–19 June 2008.
Structural Coupling of 11-cis-7-Methyl-retinal and Amino Acids at the Ligand Binding Pocket of Rhodopsin†
Article first published online: 25 FEB 2009
© 2009 The Authors. Journal Compilation. The American Society of Photobiology
Photochemistry and Photobiology
Volume 85, Issue 2, pages 485–493, March/April 2009
How to Cite
Aguilà, M., Toledo, D., Morillo, M., Dominguez, M., Vaz, B., Alvarez, R., De Lera, A. R. and Garriga, P. (2009), Structural Coupling of 11-cis-7-Methyl-retinal and Amino Acids at the Ligand Binding Pocket of Rhodopsin. Photochemistry and Photobiology, 85: 485–493. doi: 10.1111/j.1751-1097.2009.00535.x
- Issue published online: 25 FEB 2009
- Article first published online: 25 FEB 2009
- Received 14 August 2008, accepted 5 January 2009
It was previously shown that opsin can be regenerated with the newly synthesized 11-cis-7-methyl-retinal forming an artificial visual pigment. We now extend this study to include mutants at positions close to the retinal to further dissect the interactions of native and artificial chromophores with opsin. Several mutants at M207, W265 and Y268 have been obtained and regenerated with 11-cis-retinal and the 7-methyl analog. M207 is the site of the point mutation M207R associated with the retinal degenerative disease retinitis pigmentosa. All the studied mutants regenerated with 11-cis-retinal except for M207C which proved to be completely misfolded. The naturally occurring M207R mutant formed a pigment with an unprotonated Schiff base linkage, altered photobleaching and low MetarhodopsinII stability. Mutants regenerated with the 7-methyl analog showed altered photobleaching reflecting a structural perturbation in the vicinity of M207. The newly obtained mutants at M207 also showed reduced levels of transducin activation with M207R showing essentially no transducin activation. Our results highlight the tight coupling of the vicinity of C7 of retinal and M207 and support the involvement of this amino acid residue in the conformational changes associated with rhodopsin photoactivation.