Table 4.

Rate and equilibrium constant values obtained from the global fits of the Flip and Flip + Open to three independent single-channel data sets

Rate and equilibrium constants Unit Flip (Scheme 3) Flip + Open (Scheme 3a) 
α′3 s−1  19,200 ± 21% 
β′3 s−1  1,590 ± 16% 
α1 s−1 21,000 ± 99%  
β1 s−1 24,000 ± 67%  
α2 s−1 31,000 ± 62% 12,000 ± 48% 
β2 s−1 124,000 ± 55% 125,000 ± 5% 
α3 s−1 88 ± 24% 120 ± 18% 
β3 s−1 37,600 ± 23% 61,600 ± 22% 
γ1 s−1 0.0491 ± 81%  
δ1 s−1 0.00014 ± 90%  
γ2 s−1 3,260 ± 46% 758 ± 48% 
δ2 s−1 421 ± 84% 87 ± 81% 
γ3 s−1 5,920 ± 31% 10,900 ± 10% 
δ3 s−1 6,820 ± 28% 4,580 ± 18% 
k s−1 156 ± 26% 158 ± 9% 
k+ M−1 s−1 1.14 × 104 ± 14% 2.97 × 104 ± 38% 
kf− s−1 175,000 ± 93% 44,400 ± 9% 
kf+ M−1 s−1 5.23 × 108 ± 98% 7.35 × 107 ± 72% 
E3R = β3R3R   0.085 ± 5% 
E1 = β11  130 ± 54%  
E2 = β22  4.7 ± 62% 21 ± 58% 
E3 = β33  430 ± 4% 507 ± 4% 
F1 = δ11  0.0048 ± 55%  
F2 = δ22  0.088 ± 55% 0.10 ± 60% 
F3 = δ33  1.6 ± 55% 0.41 ± 8% 
KR = k/k+ mM 15 ± 31% 6.9 ± 36% 
Kf = kf−/kf+ mM 0.81 ± 31% 1.3 ± 36% 
Eeff  230 ± 27% 150 ± 10% 
EC50 mM 1.37 ± 15% 1.40 ± 39% 
nH  2.43 ± 1% 2.35 ± 5% 
Rate and equilibrium constants Unit Flip (Scheme 3) Flip + Open (Scheme 3a) 
α′3 s−1  19,200 ± 21% 
β′3 s−1  1,590 ± 16% 
α1 s−1 21,000 ± 99%  
β1 s−1 24,000 ± 67%  
α2 s−1 31,000 ± 62% 12,000 ± 48% 
β2 s−1 124,000 ± 55% 125,000 ± 5% 
α3 s−1 88 ± 24% 120 ± 18% 
β3 s−1 37,600 ± 23% 61,600 ± 22% 
γ1 s−1 0.0491 ± 81%  
δ1 s−1 0.00014 ± 90%  
γ2 s−1 3,260 ± 46% 758 ± 48% 
δ2 s−1 421 ± 84% 87 ± 81% 
γ3 s−1 5,920 ± 31% 10,900 ± 10% 
δ3 s−1 6,820 ± 28% 4,580 ± 18% 
k s−1 156 ± 26% 158 ± 9% 
k+ M−1 s−1 1.14 × 104 ± 14% 2.97 × 104 ± 38% 
kf− s−1 175,000 ± 93% 44,400 ± 9% 
kf+ M−1 s−1 5.23 × 108 ± 98% 7.35 × 107 ± 72% 
E3R = β3R3R   0.085 ± 5% 
E1 = β11  130 ± 54%  
E2 = β22  4.7 ± 62% 21 ± 58% 
E3 = β33  430 ± 4% 507 ± 4% 
F1 = δ11  0.0048 ± 55%  
F2 = δ22  0.088 ± 55% 0.10 ± 60% 
F3 = δ33  1.6 ± 55% 0.41 ± 8% 
KR = k/k+ mM 15 ± 31% 6.9 ± 36% 
Kf = kf−/kf+ mM 0.81 ± 31% 1.3 ± 36% 
Eeff  230 ± 27% 150 ± 10% 
EC50 mM 1.37 ± 15% 1.40 ± 39% 
nH  2.43 ± 1% 2.35 ± 5% 

The fits assume that the binding sites are equivalent and independent and therefore constrain the binding and unbinding rates to be the same if the conformation is the same, regardless of the number of molecules bound. This constraint was implemented by the following equations: k+1 = k+2 = k+3 = k+; k−1 = k−2 = k−3 = k, and kf+1 = kf+2 = kf+3 = kf+; kf−2 = kf−3 = kf−. In addition, one rate constant in each cycle was fixed by the constraint of microscopic reversibility (Colquhoun et al., 2004). The equilibrium constants E, F, and K, effective efficacy, Eeff, and the EC50 and Hill slope values for the Popen curve were calculated from the rate constants for each set and then averaged. Values are means ± coefficient of variation (i.e., SD of the mean expressed as a percentage of the mean).

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