Figure 3.

Simulations of four models with a monomer conformation change as a requirement for dimer formation. Searches for the six unknown rate constants gave good fits to the experimental data. Symbols are the experimental measurements. Smooth curves are numerical simulations of the model. (A, C, E, and G) Time courses of the concentration of polymerized actin measured from 7.5% pyrenyl-Mg-ATP-actin fluorescence for four models: (A) one monomer salt-induced conformational change model, (C) one monomer equilibrated conformational change model, (E) two monomer salt-induced conformational change model, and (G) two monomer equilibrated conformational change model. (B, D, F, and H) PLEs of the actin nucleation parameters for (B) the one monomer salt-induced conformational change model, (D) one monomer equilibrated conformational change model, (F) two monomer salt-induced conformational change model, and (H) two monomer equilibrated conformational change model. Symbols correspond to the RSS from best-fit values for each fixed value of the rate constant plotted on the x axis. The red line indicates the 95% CI. The two intersections of the curves give the range in which each parameter is identifiable. To see the figure in color, go online.