Fig. 4 ∣. Photocurrents and photochemical conversion upon single quantum excitation.

a, Photocurrent traces (thin solid lines) recorded from HcKCR1 in response to laser flashes upon 20-mV voltage increments superimposed with their multiexponential approximations (thick dashed lines). b, Voltage dependence of the three kinetic components of channel currents. c, Dependence of the channel current V_rev with 130 mM KCl in the bath and pipette on bath pH (mean ± s.e.m., n = 3, 8 and 6 cells from three independent experiments for pH 5.4, 7.4 and 9.4, respectively). d, Timecourse of the peak current recovery (mean ± s.e.m., n = 5 cells from three independent experiments). e, Transient absorbance changes (blue and black) and channel current (red). f, Photocurrent traces in the absence of permeant metal cations at bath pH 7.4. g, Voltage dependence of active current at different bath pH in the absence of permeant metal cations. h, Transient absorbance changes at 400 nm (blue), compared with active and passive (channel) currents (red and black, respectively). i, Photocurrent traces in the absence of permeant metal cations at bath pH 9.4. Source data are provided.