BclxL changes conformation upon binding to wild-type but not mutant p53 DNA binding domain

Franz Hagn, Christian Klein, Oliver Demmer, Natasha Marchenko, Angelina Vaseva, Ute M. Moll, Horst Kessler

Research output: Contribution to journalArticlepeer-review

68 Scopus citations


p53 can induce apoptosis through mitochondrial membrane permeabilization by interaction of its DNA binding region with the anti-apoptotic proteins BclxL and Bcl2. However, little is known about the action of p53 at the mitochondria in molecular detail. By using NMR spectroscopy and fluorescence polarization we characterized the binding of wildtype and mutant p53 DNA binding domains to BclxL and show that the wild-type p53 DNA binding domain leads to structural changes in the BH3 binding region of BclxL, whereas mutants fail to induce such effects due to reduced affinity. This was probed by induced chemical shift and residual dipolar coupling data. These data imply that p53 partly achieves its pro-apoptotic function at the mitochondria by facilitating interaction between BclxL and BH3-only proteins in an allosteric mode of action. Furthermore, we characterize for the first time the binding behavior of Pifithrin-μ, a specific small molecule inhibitor of the p53-BclxL interaction, and present a structural model of the protein-ligand complex. A rather unusual behavior is revealed whereby Pifithrin-μ binds to both sides of the protein-protein complex. These data should facilitate the rational design of more potent specific BclxL-p53 inhibitors.

Original languageEnglish (US)
Pages (from-to)3439-3450
Number of pages12
JournalJournal of Biological Chemistry
Issue number5
StatePublished - Jan 29 2010
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Biochemistry
  • Cell Biology


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