Fig. 4. TA spectra, formation kinetics traces, and decay kinetics traces for 2MP˙-C32 (top row) and 4MP˙-C32 (bottom row). (A and D): TA difference spectra recorded at pH 6.5 (±0.1) following a 500 ms 447.5 nm LED pulse. (B and E): TA kinetic traces recorded at pH 8.5 (±0.1) following a 10 ns laser pulse at 460 nm, monitored at 410 nm (2MP-α3C, orange) or 450 nm (4MP-α3C, green), and single-exponential fits (black) following the oxidation of MP-C32 by [Ru(bpy)3]3+; traces without protein are shown in gray. (C and F): decay kinetics recorded at pH 6.5 (±0.1) following a 500 ms 447.5 nm LED pulse, monitored at 380 nm (2MP˙-α3C), and 500 nm (4MP˙-α3C), where black lines show second-order fits. Samples contained 230-590 μM protein, 30 μM [Ru(bpy)3]2+, and 4–5 mM [Co(NH3)5Cl]2+.
