Extended Data Fig. 7 ∣. Extended analysis of photocurrents and photochemical conversion upon single quantum excitation.

a, Photocurrent traces (thin solid lines) recorded from HcKCR1 in response to 6-ns laser flashes at 20-mV voltage increments under indicated ionic conditions and their multiexponential approximations (dashed lines). b, The time constants (τ) of the three kinetic components of channel currents at −60 (red) and 0 (black) mV (mean ± sem). The data for individual cells are shown as circles; mean ± sem, as lines (n = 16 cells for fast opening, 13 cells for slow opening at −60 mV, 10 cells for slow opening at 0 mV, and 17 cells for closing). *, P = 0.017 **, P = 0.06; n.s. (not significant), P = 0.877 by the two-sided Mann–Whitney test. Statistics source data are provided. c, The voltage dependence of the three kinetic components of channel currents. d, Peak amplitude channel currents recorded at varied time intervals between laser flashes. The datapoints are mean ± sem, n = 5 cells. Statistics source data are provided. e, Laser flash-induced absorption changes of HcKCR1 in detergent (black) and Pichia membranes (red). Experimental data are shown as thin solid lines, and their multiexponential approximations, as dashed lines. f, HcKCR1 photocurrent traces in the absence of permeant metal cations at bath pH 5.4. Experimental data are shown as thin solid lines, and their multiexponential approximations, as dashed lines.