Distributions of tumble bias (left) and run speed (right) in experiments (black) and simulations (red) for wild‐type cells without (A) or with (B) a gradient, and mutant strains in a gradient induced with 100 μM (C) or 10 μM (D) IPTG. Inset of (D) shows the same data as (D) for a subset of low tumble bias. Tumble bias distributions of the simulated cells (left, red) were matched to the experimental tumble bias distribution (left, black) by altering the mean number of CheR proteins expressed per cell. Following previous reports (Li & Hazelbauer,
2004), a mean of 140 molecules/cell was used for wild‐type diffusion (A) and drift (B). For the mutants, we used a mean of 120 molecules/cell for induction with 100 μM IPTG (C) and a mean of 13 molecules/cell for induction with 10 μM IPTG. Speed distributions of the simulations (right, red) were normally distributed with the following means ± SDs: (A) 30 ± 7 μm/s; (B) 26 ± 6 μm/s; (C) 20 ± 5 μm/s; (D) 21 ± 6 μm/s.
