Fig. 4. Comparison of conformational states of β-subunits.

Superposition (on the N-terminal β-barrel) of the four main conformational states seen in the TF₁(βE190D) (this study; ${\beta }_{0^{\circ }}^{\mathrm{HC}}\left(\mathrm{TP}\right)$, ${\beta }_{200^{\circ }}^{\mathrm{C}}\left({\mathrm{TP}}^{*}\right)$, ${\beta }_{240^{\circ }}^{\mathrm{HO}}\left(\mathrm{DP}\bullet \mathrm{P}\right)$, and ${\beta }_{320^{\circ }}^{\mathrm{O}}\left(\mathrm{DP}\right)$), and the half-open state observed for bMF₁²⁰ (pdb1h8e). ${\beta }_{200^{\circ }}^{\mathrm{C}}\left({\mathrm{TP}}^{*}\right)$ (black) is in a fully closed state, ${\beta }_{320^{\circ }}^{\mathrm{O}}\left(\mathrm{DP}\right)$ (red) is in a fully open state, ${\beta }_{0^{\circ }}^{\mathrm{HC}}\left(\mathrm{TP}\right)$ and ${\beta }_{240^{\circ }}^{\mathrm{HO}}\left(\mathrm{DP}\bullet \mathrm{P}\right)$ are intermediate structures that are either half closing or half opening, and ${\beta }_{320^{\circ }}^{\mathrm{HC}}\left(1\mathrm{h}8\mathrm{e}\right)$ is an intermediate structure of bMF₁ similar to the open conformation. a Individual unique conformations compared to one other and viewed from the side. b Unique conformations superimposed and viewed from below.