The properties of light-elicited currents of wt-ChR2 and ChR2 mutants in HEK cells.

The peak and plateau currents for all mutants, except L132A/T59S and L132S/T159A, were elicited by a 1-s light pulse. The peak currents for the L132A/T59S and L132S/T159A mutants were elicited by a 10-ms light pulse. The τon and τoff constants were obtained by fitting a single exponential function to the decaying phase of the currents. The light intensities are presented with neutral density (ND) attenuation. The light intensity without (ND = 0) is 1.2×1018 photons/cm2s. The data are presented as the mean ± SEM.