The central region of HDM2 provides a second binding site for p53.
HDM2 is a negative regulator of p53 that inhibits its transcriptional activity and subjects it to degradation by an E3 ligase activity. The primary binding site for HDM2 on p53 is located in its N-terminal domain. A second site on the p53 core domain (p53C) binds to an unidentified site in HDM2. We found that this site is in its acidic domain and part of the zinc finger domain by examining the interaction of full-length and domain constructs of p53 with the N-terminal region of HDM2 and peptide arrays derived from the full-length protein. NMR spectroscopy showed that peptides derived from this region of HDM2 bound to residues in the specific DNA-binding site of p53C. The peptides were displaced from the site by gadd45 sequence-specific DNA. Phosphorylation of single amino acids in the central domain of HDM2 did not abolish the interaction between the HDM2-derived peptides and p53C. We speculate that this second binding site helps in stabilizing the interaction between HDM2 and p53 during p53 degradation.
Yu
Grace W
GW
Centre for Protein Engineering, Medical Research Council, Hills Road, Cambridge CB2 2QH, United Kingdom.
Rudiger
Stefan
S
Veprintsev
Dmitry
D
Freund
Stefan
S
Fernandez-Fernandez
M Rosario
MR
Fersht
Alan R
AR
D000595:Amino Acid Sequence; D019540:Area Under Curve; D001665:Binding Sites; D001667:Binding, Competitive; D002151:Calorimetry; D004247:DNA / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D005454:Fluorescence Polarization; D016158:Genes, p53; D006801:Humans; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D016159:Tumor Suppressor Protein p53 / Q000737:chemistry* / Q000378:metabolism; D016335:Zinc Fingers; D000097642:GADD45 Proteins
D004247:DNA; D018076:DNA, Complementary; D047908:Intracellular Signaling Peptides and Proteins; D010455:Peptides; D016159:Tumor Suppressor Protein p53; D000097642:GADD45 Proteins