title: Crystallization and crystal properties of squid rhodopsin.
abstract: Rhodopsin, a photoreceptor membrane protein in the retina, is a prototypical member of the G-protein-coupled receptor family. In this study, rhodopsin from the retina of the squid Todarodes pacificus was treated with V8 protease to remove the C-terminal extension. Truncated rhodopsin was selectively extracted from the microvillar membranes using alkyl glucoside in the presence of zinc ions and was then crystallized by the sitting-drop vapour-diffusion method. Of the various crystals obtained, hexagonal crystals grown in the presence of octylglucoside and ammonium sulfate diffracted to 2.8 A resolution. The diffraction data suggested that the crystal belongs to space group P6(2), with unit-cell parameters a = b = 122.1, c = 158.6 A. Preliminary crystallographic analysis, together with linear dichroism results, suggested that the rhodopsin dimers are packed in such a manner that their transmembrane helices are aligned nearly parallel to the c axis.
authors.affiliation: Department of Physics, Graduate School of Science, Nagoya University, Nagoya, Japan.
authors.forename: Midori
authors.initials: M
authors.lastname: Murakami
authors.forename: Rei
authors.initials: R
authors.lastname: Kitahara
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Gotoh
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Kouyama
mesh_terms: D000818:Animals; D003460:Crystallization; D018360:Crystallography, X-Ray; D049832:Decapodiformes / Q000648:ultrastructure; D012243:Rhodopsin / Q000737:chemistry* / Q000302:isolation & purification / Q000648:ultrastructure
chemical_list: D012243:Rhodopsin