Probing the Energy Landscape of Activation Gating of the Bacterial Potassium Channel KcsA
Figure 3
Conformational changes of F103 during activation gate opening and SF conformations of channel states.
A) Analysis of χ1 angle dynamics of F103 (in ten opening ED simulations). Changes of the F103 orientation (χ1 angle) were measured over time. An angle of −70° indicates the “up” state (blue) while an angle of −180° represents the “down” state (yellow). The percentage of state was calculated from the end states at 20 ns of the ten ED simulations. B) SF and P-helix of the closed crystal structure (gray). Blue spheres represent K+ ions. C) SF and P-helix at the end of the 20 ns ED simulation structure with deprotonated E71 (yellow). D) SF and P-helix at the end of the 20 ns ED simulation structure with protonated E71 (yellow). E) SF and P-helix of the open inactivated crystal structure (gray). The G77 conformation defines the SF state as it was shown by Cuello et al. [12].