Fig. 5: Comparison with other K structures.

a Superimposition of various K structures. Carbon atoms in 1QK0 reported by Edman et al.¹³, 1M0K by Schobert et al.¹⁴, 1IXF by Matsui et al.¹⁵, 6G7K by Nogly et al.¹⁸, and 6GA6 by Nass Kovacs et al.¹⁹, 7Z0C by Borshchevskiy et al.¹⁶ and 7XJC reported in this work are colored in green, yellow, cyan, navy orange and magenta, respectively, while nitrogen (blue) atoms are in common. b Distribution of torsion angles of conjugated double bonds (C13−C14 and C15−Nς) in retinal. The torsion angles for the K structures are plotted as filled circles in the same colors as used for the carbon atoms in panel a, while those for the corresponding ground state structures (1QKP¹³, 1M0L¹⁴, 1IW6¹⁵, 6G7H¹⁸, 6RMK¹⁹, 7Z09¹⁶ and 7XJD) are plotted as filled diamonds. For the K and ground state structures in this study, the standard deviations calculated from three structures for each are shown as error bars on the mean values shown as hollow circles. Data points for respective structures in this study are shown as crosses.