Yu Grace W, Rudiger Stefan, Veprintsev Dmitry, Freund Stefan, Fernandez-Fernandez M Rosario, Fersht Alan R
Centre for Protein Engineering, Medical Research Council, Hills Road, Cambridge CB2 2QH, United Kingdom.
Proc Natl Acad Sci U S A. 2006 Jan 31;103(5):1227-32. doi: 10.1073/pnas.0510343103. Epub 2006 Jan 23.
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.
HDM2是p53的负调节因子，可抑制其转录活性，并通过E3连接酶活性使其降解。HDM2在p53上的主要结合位点位于其N端结构域。p53核心结构域（p53C）上的第二个位点与HDM2中一个未确定的位点结合。通过检测p53全长和结构域构建体与HDM2 N端区域以及源自全长蛋白的肽阵列的相互作用，我们发现该位点位于其酸性结构域且是锌指结构域的一部分。核磁共振光谱显示，源自HDM2该区域的肽与p53C特定DNA结合位点中的残基结合。这些肽被gadd45序列特异性DNA从该位点置换。HDM2中央结构域中单个氨基酸的磷酸化并未消除源自HDM2的肽与p53C之间的相互作用。我们推测，这个第二个结合位点有助于在p53降解过程中稳定HDM2与p53之间的相互作用。
