Relations between the structural and conformational states determined, respectively, from the crystal structures and in the polarization study. (A) The four mean orientations of the tracked helix in the four conformational states, determined over the examined range of the Agm²⁺ concentration, are represented by a set of four unit vectors (closed heads) in the local coordinates, whereas those for four structural states by another set of unit vectors (open heads), which are E_O (blue) (PDB: 7O82) and E_X (yellow) (PDB: 3L1L) of AdiC, I_O of BasC (orange) (PDB: 6F2G), and I_X of ApcT (cyan) (PDB: 3GIA). The vectors for the conformational states, color coded for the states, are drawn according to θ and φ values obtained from the corresponding distributions. The two sets of vectors are overlaid according to the combined least-distance squares. (B) Scatter plots of mean θ versus φ values for four conformational states (closed circles), which are compared with those for the four structural states (open circles); all are color coded for states. (C) The inverse values of combined least-distance squares between the locations of the arrow heads of the two compared groups (open versus closed) in panel A plotted against the identification (ID) numbers for all 24 possible combination sequences among them. The two cases corresponding to configurations 1 and 2 are indicated by the arrows.