Representative BLI sensograms showing the real-time concentration-dependent (each concentration depicted by a different color indicated in the box below) binding of WT Mtb LexA and its variants, LexAΔ18aa, and LexAΔ24aa to biotinylated 44 mer dnaE2 ‘SOS’ box at physiological pH (A–C), the kinetic parameters obtained from which are tabulated in Table 2. The corresponding response versus concentration curves has been plotted in (D–F) from the results of three independent experiments. (G) Representative BLI sensogram showing absence of binding of LexA RKG/AAA to biotinylated 44 mer dnaE2 ‘SOS’ box at physiological pH.