Figure 6.

Simultaneously determined parameters using the maximum likelihood method with the two-state model (2-state, blue), four-state model that includes acceptor blinking (4-state, green), two-state model with donor delay time information (2-state/Ds, orange), four-state model with donor delay time information (4-state/Ds, purple), and modified two-state model that includes acceptor blinking (2-state/Dbs, black). (a) Parameters from the analysis of experimental data. E is the FRET efficiency (folded: circle; unfolded: square), relaxation rate k is normalized to the experimental values obtained from the 4-state/Ds analysis (dashed line), p_F is the fraction of the folded state, donor lifetime τ_D (folded: circle; unfolded: square) is normalized to the donor lifetime without the acceptor (τ_D⁰), k_b is the rate coefficient from the dark state to the bright state of the acceptor, p_b⁰ (= k_b/(k_b + k_d⁰)) is the fraction of the bright state population at the reference photon count rate n = 100 ms⁻¹. The average photon count rates are 65.3, 72.6, and 54.4 ms⁻¹, for α₃D, gpW, and the WW domain, respectively. (b) Parameters obtained from the maximum likelihood analysis of recolored data using the experimental 4-state/Ds parameters (dashed lines). The color schemes and symbols are the same as those in (a).