Fig. 2

a dsDNA extension-experiments with different MTX concentrations. Open circles show the experimental data and solid lines represent the fitting to the WLC model. b Persistence length P of dsDNA in dependence of drug concentrations (green dots). The zones below and beyond the threshold concentration were approximated by a straight line (< 3 µM) and a zero slope line (> 3 µM), c plot of fractional elongation of DNA γ with drug concentrations. Green dots show the experimental data that were approximated to the McGhee-von Hippel model (solid line)