Solution structure of the TAZ2 (CH3) domain of the transcriptional adaptorprotein CBP

The TAZ2 (CH3) domain of the transcriptional adapter protein CBP has been i mplicated in direct functional interactions with numerous cellular transcri ption factors and viral oncoproteins. The solution structure of the TAZ2 do main of murine CBP has been determined by nuclear magnetic resonance (NMR). The protein adopts a novel helical fold stabilized by three zinc ions, eac h of which is bound to one histidine and three cysteine ligands in HCCC-typ e motifs. Each zinc-binding site is formed from the carboxy terminus of an alpha -helix, a short loop, and the amino terminus of the next alpha -helix . A peptide derived from the N-terminal transactivation domain of p53 binds specifically to one face of the TAZ2 domain. The close similarities betwee n the TAZ2 and TAZ1 (CH1 domain of CBP/p300) sequences suggest that both do mains will adopt similar three-dimensional structures. (C) 2000 Academic Pr ess.