Autodisplay dimerization assay: E. coli strain BL21 (DE3) [B, F -, dcm, ompT, lon, hsdS (rB -mB -), gal, λ(DE3)] pETSH-3 Hsp90 encoding CtxB signal peptide, AIDA-I autotransporter and Hsp90 was used for the surface display of Hsp90. E. coli strain BL21 (DE3)[B, F -, dcm, ompT, lon, hsdS (rB -mB -), gal, λ(DE3)] pETSH-3 SDH08 encoding CtxB signal peptide, AIDA-I autotransporter and sorbitol dehydrogenase was used as control . Recombinant bacteria were routinely grown at 37 °C in lysogeny broth (LB) containing carbenicillin (100 µg/ml). Cells were grown to the mid log phase (OD 600 = 0.5) and the protein expression was induced by adding 1 mM IPTG for 16 h at 30 °C. Cells were then washed three times and suspended in PBS to an OD 600 = 0.35 in a final volume of 100 µl. Prior to p53-FITC incubation at a final concentration of 1 µM for 1 hour at RT in the dark, cells were incubated for 15 minutes either with or without inhibitor. Subsequently, cells were washed three times with PBS containing 0.1 % Tween-20 to avoid unspecific binding. The cellular fluorescence was measured with a FACS Aria III (BD, Heidelberg, Germany), using 488 nm as excitation wavelength, 530 nm for detection and the mean fluorescence value of at least 50,000 events for each measurement was determined.