Fig. 3.
Bcl-xL forms stable dimers in solution that exchange in presence of cBid. a Possible reaction scenarios between cBid and Bcl-xL in solution tested by modeling. b FCCS kinetic experiment on Bcl-xLR/Bcl-xLG dimerization in absence and presence of cBid (exemplary experiment out of n = 3). c, d Best fit of ODE model considering scenario 2 to the evolution of fluorescent Bcl-xL species based on the data shown in b. The upper and the lower panels show two independent experiments (mean and error bars as s.d. of three technical repetitions) with the Y-axis corresponding to the concentration of Bcl-xL particles. The first data point in presence of cBid is introduced as t = 1 min and highlighted in the figure by asterisk. This is applicable as each data point had a total FCS measurement time of 2 min. e Likelihood profiles of model parameters that define rate constants. The fitted parameter is shown as a blue dot, the reoptimized SSR is shown as black line and the dashed grey line indicates the confidence limit. FCCS fluorescence cross correlation spectroscopy