Fig. 4.

(A) Kinetic measurements of photoreduction. N_r(t) increases with irradiation time and is fitted with N_r = N_r(∞)(1− exp(−σJt)) and N_r(∞) = σ_r / σ with σ = σ_r + σ_o. The data for Pa cyt c₅₅₁ WT, and F7A, and cyt c are shown as circles, triangles, and squares, respectively. The fitted curves are shown in red. Parameters used in the fits are summarized in Table 1. The photon flux was J = 7.3 × 10¹⁵ photons/s-cm² and 4.5 × 10¹⁶ photons/s-cm² for the Pa cyt c₅₅₁ samples and for hh cyt c, respectively. Division by J yields the data as a function of time. (B) The photoreduction cross-sections are plotted as a function of ruffling distortion and fit using an exponential function with both hh cyt c and Pa cyt c₅₅₁ samples (solid) or only Pa cyt c₅₅₁ (dashed).