Skip to main content
. 2012 Nov 19;7(11):e50018. doi: 10.1371/journal.pone.0050018

Figure 4. Kinetic parameters for single serine ChR2 constructs.

Figure 4

Kinetic values were obtained by fitting ChR2 photocurrents to a standard biexponential equation. All parameters were calculated in 115 mM Na+ solution at pH 9. For on and decay times, traces were fit at −120 mV to ensure ChR2 was in the dark adapted state. Values reported as mean±S.E.M (n = 8–23). Significant differences are marked with a *(P<0.05). (A) Summary of photocurrent exponential fits. On time was calculated from baseline current to peak current, decay time was calculated from peak to stationary current, and off time was calculated from stationary to baseline current when the light is switched off. (B) Off rate comparison of the slow G224S mutant versus WT at different membrane potentials. The off rate of ChR2 had a strong dependence on the holding potential of the cell. Diamond, WT; crossed X, G224S. All values were statistically significant (as described in C) (C) Summary of kinetic parameters and inactivation ratios for single serine ChR2 mutants. Values are reported as mean±S.E.M (n = 8–23). Statistically significant values are denoted by a *(P<0.05).