<p>The energy perturbation caused by mutations for steady-state activation, rates of activation and deactivation are shown as absolute values and mapped onto the S4–S5 linker viewed parallel to the membrane. The colour scale in steady-state activation A, was normalised to the value corresponding to the largest perturbation (−13.33 kJ mol<sup>−1</sup>) whereas in the case of activation B, and deactivation C, the colour scale spans 0 to 4.2 kJ mol<sup>−1</sup>. B. Perturbations to rates of activation measured at (i) a low voltage gradient: <i>V</i> = <i>V</i><sub>0.5</sub>+40 mV and (ii) a high voltage gradient: <i>V</i> = <i>V</i><sub>0.5</sub>+180 mV. C. Perturbations to rates of deactivation (fast component) measured at (i) a low voltage gradient: <i>V</i> = <i>V</i><sub>0.5</sub>−40 mV and (ii) a high voltage gradient: <i>V</i> = <i>V</i><sub>0.5</sub>−130 mV.</p
