Disorder profile and functionality of p53. Intrinsic disorder was predicted by the PONDR® VLXT. Segments with scores above 0.5 correspond to disordered regions, while those below 0.5 correspond to ordered regions/binding sites. p53 is at the center of a large signaling network, regulating expression of genes involved in a variety of cellular processes and interacting with a large number of other proteins. The interaction sites are signaled by downward spikes in the plot of the predicted disorder. The structures of the complexes containing various p53 binding regions are displayed around the predicted disorder pattern. In complexes, the structures of p53 segments bound to their partners are shown in different colors. These color codes are also used for bars in the PONDR® VLXT plot to indicate the positions of the regions of known structure in the context of the intrinsic disorder predictions. The Protein Data Bank IDs and partner names for the structures (from upper left, clockwise) are as follows: (1tsr DNA), (1gzh 53BP1), (1q2d gcn5), (3sak p53 (tet dom)), (1xqh set9), (1h26 cyclinA), (1ma3 sirtuin), (1jsp CBP bromo domain), (1dt7 s100bb), (2h1l sv40 Large T antigen), (1ycs 53BP2), (2gs0 PH), (1ycr MDM2), and (2b3g rpa70).