Structural Basis for p300 Taz2-p53 TAD1 Binding and Modulation by Phosphorylation

Abstract

Coactivators CREB-binding protein and p300 play important roles in mediating the transcriptional activity of p53. Until now, however, no detailed structural information has been available on how any of the domains of p300 interact with p53. Here, we report the NMR structure of the complex of the Taz2 (C/H3) domain of p300 and the N-terminal transactivation domain of p53. In the complex, p53 forms a short α helix and interacts with the Taz2 domain through an extended surface. Mutational analyses demonstrate the importance of hydrophobic residues for complex stabilization. Additionally, they suggest that the increased affinity of Taz2 for p531-39 phosphorylated at Thr18 is due in part to electrostatic interactions of the phosphate with neighboring arginine residues in Taz2. Thermodynamic experiments revealed the importance of hydrophobic interactions in the complex of Taz2 with p53 phosphorylated at Ser15 and Thr18. © 2009 Elsevier Ltd. All rights reserved.