X-ray crystallographic analysis of 9-cis-rhodopsin, a model analogue visual pigment.
Recent progress in high-resolution structural study of rhodopsin has been enabled by a novel selective extraction procedure with rod photoreceptor cells. In this study, we applied the method for rapid and efficient preparation of a purified analogue pigment using bovine rod outer segment membranes with 9-cis-retinal. After complete bleaching of the membranes and subsequent regeneration with the exogenous retinal, 9-cis-rhodopsin is selectively extracted from the membranes using combination of zinc and heptylthioglucoside. The solubilized sample, even with a small amount of contaminating retinal oximes, is shown to be pure enough for three-dimensional crystallization. The X-ray diffraction from 9-cis-rhodopsin crystals was examined and the electron density map at 2.9 angstroms resolution in the chromophore region can be fitted well with the model of 9-cis-retinal Schiff base.
Nakamichi
Hitoshi
H
Biological Information Research Center, National Institute of Advanced Industrial Science and Technology, 2-41-6 Aomi, Koto-ku, Tokyo 135-0064, Japan.
Okada
Tetsuji
T
D000818:Animals; D002417:Cattle; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D010777:Photochemistry; D012243:Rhodopsin / Q000737:chemistry* / Q000302:isolation & purification; D012374:Rod Cell Outer Segment / Q000737:chemistry; D013053:Spectrophotometry; D055672:Static Electricity
D012243:Rhodopsin