Fig. 3: Conformational rearrangements of the Sox2 C-IDR upon binding DNA and nucleosomes.

a Single-molecule transfer efficiency histograms of fluorescently labelled 15 bp DNA containing Sox2 binding site, with different concentrations of unlabelled full-length Sox2. The peak at E ~ 0 corresponds to a population of molecules without an active acceptor. b The corresponding binding isotherms with fits (solid lines) to a 1:1 binding model, for both full-length Sox2 and the isolated DBD. Data are presented as mean values +/- SEM, estimated from dilution errors. Single-molecule transfer efficiency histograms of full-length Sox2 fluorescently labelled in the C-IDR, in the absence (blue) and presence of (c) 15 bp DNA (red) or (d) 197 bp nucleosomes (purple). Fluorescence lifetime analysis of Sox2 in the absence (blue) and presence of (e) DNA (red) or (f) nucleosomes (purple). g ¹H¹⁵N HSQCs of free Sox2 (blue) and Sox2 in complex with 15 bp unlabelled DNA (red). Zoomed-in regions show resonances that are affected or unaffected by DNA binding. Plots of (h) CSPs for Sox2 upon DNA binding and ¹⁵N-relaxation data (i–k) R₂ for free Sox2 (blue) and DNA-bound Sox2 (red, i), isolated C-IDR (grey, j), and the respective difference plot (C-IDR - free Sox2 (grey), DNA bound Sox2 - free Sox2 (red), k). Error bars indicate 95% confidence intervals centred on values obtained from the fitting procedure. Source data are provided as a Source Data file.