Structural basis of DNA recognition by p53 tetramers

Area of Science:

• Molecular Biology
• Structural Biology
• Cancer Research

Background:

• The tumor-suppressor protein p53 is a critical defense against cancer.
• p53 responds to cellular stress by binding DNA and regulating gene expression for cell-cycle arrest or apoptosis.

Purpose of the Study:

• To present high-resolution crystal structures of human p53 core domain complexes with DNA half-sites.
• To elucidate the structural basis of sequence-specific DNA binding by p53.

Main Methods:

• X-ray crystallography to determine the structure of p53-DNA complexes.
• Analysis of protein-DNA interfaces and binding affinities.

Main Results:

• High-resolution crystal structures of sequence-specific p53-DNA complexes were obtained.
• p53 forms a tetramer (dimer of dimers) on DNA, stabilized by protein-protein and base-stacking interactions.
• The protein-DNA interface varies with DNA sequence, correlating with binding affinities.

Conclusions:

• A structural framework for understanding p53 DNA binding specificity, affinity, and cooperativity is established.
• The findings suggest a model for p53 regulation involving regions outside its DNA-binding domain.