TY - JOUR
T1 - Conformational Differences among Metarhodopsin I, Metarhodopsin II, and Opsin Probed by Wide-Angle X-ray Scattering
AU - Imamoto, Yasushi
AU - Kojima, Keiichi
AU - Oka, Toshihiko
AU - Maeda, Ryo
AU - Shichida, Yoshinori
N1 - Funding Information:
This work was supported by The Kyoto University Foundation, and ISHIZUE 2019 of Kyoto University Research Development Program. The synchrotron radiation experiments were performed at the BL40B2 in the SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal Nos. 2012A1263, 2013A1136, 2014A1247, 2016A1427, and 2016B1258). A part of this work was carried out under the Cooperative Research Project Program of Research Institute of Electronics, Shizuoka University.
Funding Information:
This work was supported by The Kyoto University Foundation and ISHIZUE 2019 of Kyoto University Research Development Program. The synchrotron radiation experiments were performed at the BL40B2 in the SPring-8 with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal Nos. 2012A1263, 2013A1136, 2014A1247 2016A1427, and 2016B1258). A part of this work was carried out under the Cooperative Research Project Program of Research Institute of Electronics, Shizuoka University.
PY - 2019/10/31
Y1 - 2019/10/31
N2 - 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.
AB - 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.
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U2 - 10.1021/acs.jpcb.9b08311
DO - 10.1021/acs.jpcb.9b08311
M3 - Article
C2 - 31580080
AN - SCOPUS:85074260123
VL - 123
SP - 9134
EP - 9142
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
SN - 1520-6106
IS - 43
ER -