CRYSTAL-STRUCTURE OF THE TETRAMERIZATION DOMAIN OF THE P53 TUMOR-SUPPRESSOR AT 1.7 ANGSTROMS

The p53 protein is a tetrameric transcription factor that plays a cent ral role in the prevention of neoplastic transformation. Oligomerizati on appears to be essential for the tumor suppressing activity of p53 b ecause oligomerization-deficient p53 mutants cannot suppress the growt h of carcinoma cell lines. The crystal structure of the tetramerizatio n domain of p53 (residues 325 to 356) was determined at 1.7 angstrom r esolution and refined to a crystallographic R factor of 19.2 percent. The monomer, which consists of a beta strand and an alpha helix, assoc iates with a second monomer across an antiparallel beta sheet and an a ntiparallel helix-helix interface to form a dimer. Two of these dimers associate across a second and distinct parallel helix-helix interface to form the tetramer.