Figure 3. Energy landscape of DBD folding and classification of p53 mutants.
The populations of folded, active WT DBD (A) and R175H DBD (B) depend strongly on free zinc concentration and temperature. White circles indicate physiological T and [Zn2+]free. (C) 17 of the top 20 most common tumorigenic p53 mutations impair DBD thermodynamic stability (red box), zinc-binding affinity (green box), or both (orange box) (10°C). The remaining three are DNA-contact mutations (blue box). Open circles indicate WT DBD destabilized by urea.
Figure 3—source data 1. Stabilities and zinc-binding affinities of apoDBD variants (10°C).
ΔGapo and KZn were obtained from fits of the data in Figure 3—figure supplement 1 and Figure 3—figure supplement 2 to Equation 3 (errors are SE of the fits). KZn (direct) values were obtained from Tyr fluorescence spectra as in Figure 2A (errors are SD, n = 3). Asterisks denote that KZn could not be determined due to the presence of the extra Cys in the indicated Tyr-to-Cys mutants. Consequently, Y163C, Y205C, and Y220C are listed as stability-class mutants, but we cannot exclude the possibility that they belong to the mixed zinc-binding/stability class.
elife-61487-fig3-data1.docx (21.3KB, docx)
Figure 3—figure supplement 1. Free energy of folding versus buffered [Zn2+]free for p53 DBD mutants.
Folding energies were determined from guanidine melts of DBD mutants in EDTA-buffered [Zn2+]free, and were used to determine the zinc-free folding energies and zinc affinities presented in Figures 3C and 4. Independent experimental results were pooled and fit to Equation 3 to obtain ΔGapo and KZn, which are reported in Figure 3—source data 1 with the standard errors of the fit. No data points were rejected in any of the plots.
Figure 3—figure supplement 2. Free energy of folding versus buffered [Zn2+]free for p53 DBD mutants.
See legend to Figure 3—figure supplement 1 for details. No data points were rejected in any of the plots.