Fig. 5: PBP1b synthesis time is independent of its intrinsic affinity for LpoB. | Nature Communications

Fig. 5: PBP1b synthesis time is independent of its intrinsic affinity for LpoB.

From: The hit-and-run of cell wall synthesis: LpoB transiently binds and activates PBP1b through a conserved allosteric switch

Fig. 5

a Representative jump distance distributions (over a period of 5 steps in length) and fits of strains expressing PBP1b-Halo-WT (TU122/pAV23, blue) and PBP1b-Halo-I202F mutant (TU122/pSI237, red), alongside the fixed cell control (TU122/pAV23, grey), imaged with a fast acquisition rate (30 ms). The chosen immobile threshold is shown as a dotted line. The I202F strain exhibits a 15–20%-fold increase (p < 0.05) in the population of the bound (active) state relative to the WT sample. Data collection parameters and statistics are summarized in SI Table 4. Distributions and fits were generated using Spot-ON sp-tracking software. b Example single-particle trajectories of strains from (a) of PBP1b-Halo-WT (blue), PBP1b-Halo-I202F mutant (red) and the fixed cell control (grey) imaged with a slower acquisition rate (225 ms). Periods of immobility (active synthesis or tethering to LpoB) correspond to step-like decreases in the instantaneous step size of the diffusing particle below the threshold value of 70 nm (dotted line). The fixed cell control shows few if any rapidly diffusing particles and has much longer periods of immobility. c Dwell time distribution histograms and exponential fits of samples from (b). PBP1b-WT and the I202F mutant exhibit similar dwell times of the bound (active) state.

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