Figure 4.

Chronoamperometric measurements with the magnetic field pointing up (red line) or down (black line) in TRIS buffer containing 1 mM K₄[Fe(CN)₆]/K₃[Fe(CN)₆] at pH 9 (a) of mutant D96N bR on nickel substrates and (b) for the WT bR on nickel substrates. The dashed curves were obtained when the sample was illuminated with a 532 nm laser. Note that the current in the case of the mutant (b), when illuminated, is larger by more than a factor of 3 than that obtained with the wild-type bR (a) in the dark. Measurements were performed at the reduction potential, that is, 73 mV for wild-type and 64 mV for D96N vs the KCl-saturated calomel electrode.