title: Helical rearrangement of photoactivated rhodopsin in monomeric and dimeric forms probed by high-angle X-ray scattering.
abstract: Light-induced helical rearrangement of vertebrate visual rhodopsin was directly monitored by high-angle X-ray scattering (HAXS), ranging from Q (= 4π sin θ/λ) = 0.03 Å(-1) to Q = 1.5 Å(-1). HAXS of nanodiscs containing a single rhodopsin molecule was performed before and after photoactivation of rhodopsin. The intensity difference curve obtained by HAXS agreed with that calculated from the crystal structure of dark state rhodopsin and metarhodopsin II, indicating that the conformational change of monomeric rhodopsin in the membrane is consistent with that occurring in the crystal. On the other hand, the HAXS intensity difference curve of nanodiscs containing two rhodopsin molecules was significantly reduced, similar to that calculated from the crystal structure of the deprotonated intermediate, without a large conformational change. These results suggest that rhodopsin is dimerized in the membrane and that the interaction between rhodopsin molecules modulates structural changes.
authors: Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan. imamoto@rh.biophys.kyoto-u.ac.jp.
authors: Yasushi
authors: Y
authors: Imamoto
authors: Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan. imamoto@rh.biophys.kyoto-u.ac.jp.
authors: Keiichi
authors: K
authors: Kojima
authors: Department of Physics, Faculty of Science, Shizuoka University, Shizuoka 422-8529, Japan and Nanomaterials Research Division, Research Institute of Electronics, Shizuoka University, Shizuoka 432-8011, Japan.
authors: Toshihiko
authors: T
authors: Oka
authors: Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan. imamoto@rh.biophys.kyoto-u.ac.jp.
authors: Ryo
authors: R
authors: Maeda
authors: Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan. imamoto@rh.biophys.kyoto-u.ac.jp.
authors: Yoshinori
authors: Y
authors: Shichida
mesh_terms: D000818:Animals; D002417:Cattle; D019281:Dimerization; D055668:Photochemical Processes; D011487:Protein Conformation; D012243:Rhodopsin / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D012243:Rhodopsin