Figure 4. Bacterial speed increases with increased ActA polarity and intensity in simulations that incorporate friction.

A) 3-dimensional plot of the average bacterial speed vs. its 1^st moment and total ActA linescan intensity for 253 simulated bacteria. A range of simulated ActA polarities was chosen to correspond to the experimentally observed range (Fig. 2A). Similarly, the total ActA intensities were set to span a ten-fold range as in the experimental data. The linescan graphs along the bottom right axis display the ActA distribution for respective 1^st moment values (intensity normalized to the maximum). Actual data points are shown in red. The best-fit plane is shown in gray. B) An alternate view of the dataset shown in A, highlighting the quality of the fit and scatter around the best-fit plane. C) 3-dimensional plot of the R² value obtained when fitting the data shown in A by functions of increasing polynomial degree. As in Fig. 2C the greatest increase in R² occurs for a linear fit in ActA intensity and polarity (yellow star) –higher degree polynomials only marginally improve the fit.