Conformational differences among metarhodopsin I, metarhodopsin II, and opsin probed by wide-angle X-ray scattering

HANDLE Open Access
  • Imamoto, Yasushi
    Department of Biophysics, Graduate School of Science, Kyoto University
  • Kojima, Keiichi
    Department of Biophysics, Graduate School of Science, Kyoto University
  • Oka, Toshihiko
    Department of Physics, Faculty of Science, Nanomaterials Research Division, Research Institute of Electronics, Shizuoka University
  • Maeda, Ryo
    Department of Biophysics, Graduate School of Science, Kyoto University
  • Shichida, Yoshinori
    Research Organization for Science and Technology, Ritsumeikan University

Abstract

Among the photoproducts of vertebrate rhodopsin, only metarhodopsin II (Meta-II) preferentially adopts the active structure in which transmembrane helices are rearranged. Light-induced helical rearrangement of rhodopsin in membrane-embedded form was directly monitored by wide-angle X-ray scattering (WAXS) using nanodiscs. The change in the WAXS curve for the formation of Meta-II was characterized by a peak at 0.2 Å⁻¹ and a valley at 0.6 Å⁻¹, which were not observed in metarhodopsin I and opsin. However, acid-induced active opsin (Opsin*) showed a 0.2 Å⁻¹ peak, but no 0.6 Å⁻¹ valley. Analyses using the model structures based on the crystal structures of dark state and Meta-II suggest that the outward movement of helix VI occurred in Opsin*. However, the displaced helices III and V in Meta-II resulting from the disruption of cytoplasmic ionic lock were restored in Opsin*, which is likely to destabilize the G-protein-activating structure of opsin.

Journal

Details 詳細情報について

  • CRID
    1050564288808726272
  • NII Article ID
    120006764461
  • ISSN
    15206106
    15205207
  • HANDLE
    2433/244712
  • Text Lang
    en
  • Article Type
    journal article
  • Data Source
    • IRDB
    • CiNii Articles

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