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

• 今元, 泰

  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

抄録

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.

収録刊行物

• The Journal of Physical Chemistry B

  The Journal of Physical Chemistry B 123 (43), 9134-9142, 2019-10-31

  American Chemical Society (ACS)

詳細情報

• CRID: 1050564288808726272
• NII論文ID: 120006764461
• ISSN: 15206106
• ISSN: 15205207
• HANDLE: 2433/244712
• 本文言語コード: en
• 資料種別: journal article
• データソース種別:
  • IRDB
  • CiNii Articles