Fig. 9. A comparison of sites that had reduced effects on the selectivity of the closed state with those that affected the steepness of the voltage dependence. The upper panel shows the changes in the closed-state reversal potential (normalized for the sign and magnitude of the engineered charge change) of the sites that had significant effect on the open-state selectivity (Fig. 7). The open bars are sites that had an effect on the selectivity of the closed state that was similar in magnitude to that of the open state. The solid bars are sites that had either no significant effect on the selectivity of the closed state or an effect that was smaller than expected. The lower panel shows changes in the steepness of the voltage dependence (normalized as well) with significant changes in solid bars and non-significant changes in open bars. Positive values indicate changes that were in the direction expected from the sign of the engineered charge change.