Figure 3
The Hsp90-dependent binding of wild-type p53 protein to p21WAF1 gene promoter sequence is inhibited by LA-12 and 17-AAG. A) Wild-type p53 binding (0.125 μM tetramer) to the promoter sequence at 22°C (the main band) is not influenced by 4% DMSO (final concentration in the reaction) or LA-12 and 17-AAG dissolved in the corresponding DMSO amount. B) Hsp90β (3 μM dimer) with 5 mM ATP (final concentration in all reactions) rescues the p53 activity from inactivation at 37°C, in the presence of an increasing DMSO concentration, while LA-12 and 17-AAG inhibit Hsp90β. The LA-12 stock solution is 2× more concentrated than 17-AAG to compensate for the lower LA-12 activity. Thus both inhibitors are in corresponding DMSO amounts: 100, 200, 300 μM LA-12 and similarly 50, 100, 200 μM 17-AAG introduce 2%, 4%, 6% DMSO concentration to the reaction, respectively.