Conformational equilibria of light-activated rhodopsin in nanodiscs

著者: Ned Van Eps, Lydia N. Caro, Takefumi Morizumi, Ana Karin Kusnetzow, Michal Szczepek, Klaus Peter Hofmann, Timothy H. Bayburt, Stephen G. Sligar, Oliver P. Ernst, Wayne L. Hubbell - Proceedings of the National Academy of Sciences, PNAS 2017 被引用: 96

form defined by proton uptake and optical spectroscopic methods is reported to be the sole species present in native disk membranes. In nanodiscs, the ensemble of substates in the photoactivated receptor spontaneously decays to that characteristic of the inactive state with a lifetime of ∼16 min at 20 °C. Importantly, transducin binding to the activated receptor selects a subset of the ensemble in which multiple substates are apparently retained. The results indicate that in a native-like lipid environment rhodopsin activation is not analogous to a simple binary switch between two defined conformations, but the activated receptor is in equilibrium between multiple conformers that in principle could recognize different binding partners.