Fig. 3: SptPALM of DnaA in live E. coli MG1655 cells.
From: The Escherichia coli replication initiator DnaA is titrated on the chromosome
A Photoactivatable fluorescent protein PAmCherry2.1 was fused to DnaA in its native chromosomal locus by replacing amino acids 87-106 in Domain II of DnaA. The domains of DnaA are indicated with Roman numerals. Domain II and IIIb are depicted in light grey, yet are not specifically indicated for visualisation purposes due to their small size. On the bottom, the codon numbers of each domain of the wild-type DnaA are indicated, not accounting for the PAmCherry2.1 insertion. B Distributions of diffusion coefficients of DnaA in live E. coli cells grown in either slow, intermediate or fast growth regimes. The number of cells and tracks per histogram is shown in the upper left corner. Histograms are fitted (black line) with a theoretical description of 250,000 particles moving between a free and a bound state. On the right, kinetic rates describing the fitting are provided. C Trends of the kinetic rates kFree→Bound and kBound→Free and average bound fraction of DnaA in different growth regimes. Data are presented as mean values ± SD, derived mathematically from the fitting of diffusional distribution or from kinetic rates in (B). P-values are calculated by a two-sided T test. D Trends of DnaA mobility throughout the cell cycle. The average diffusion coefficient of each cell is plotted against the area of the cell, with the black line indicating the rolling median of the population. The grey ribbons represent the interquartile range. The magenta vertical line indicates the area at which cells initiate DNA replication. See Supplementary Fig. 4G for the area distribution of the cells. Source data are provided as a Source Data file.
