The model reproduces measured histograms.

<p>In all plots, histograms from measurements (blue) [<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004599#pcbi.1004599.ref052" target="_blank">52</a>] are plotted along with histograms from five individual simulations (gray), and histograms of those five simulations pooled together (black). The different experimental conditions are A. Increasing myosin (left to right), 1000 frames recorded at <i>f</i> = 10 Hz; B. Increasing calcium (left to right), 500 frames recorded at <i>f</i> = 3.8 Hz; and C. Decreasing ATP (left to right), 500 frames recorded at <i>f</i> = 3.8 Hz. At each calcium concentration, there is only a single fitting parameter (<i>ε</i>). With the exception of the right panel in C, agreement between simulation and measurement is good. D. For the single case where model and simulation differ, we get good agreement between simulation and measurement with only a 50nM increase in ATP concentration. Differences between simulation and experiment are therefore likely due to the system’s sensitivity to parameters, so that small differences in experimental condition lead to large changes in measurement. Note: To compare simulations with measurements [<a href="http://www.ploscompbiol.org/article/info:doi/10.1371/journal.pcbi.1004599#pcbi.1004599.ref052" target="_blank">52</a>], all plots have units of intensity, which depends on frame rate. For plot A, collected at 10 Hz, the intensity of a single GFP-S1 is <i>I</i>₁ = 45 intensity units. For plots B–D, collected at 3.8 Hz, the intensity of a single GFP-S1 is <i>I</i>₁ = 118 intensity units.