On the mechanism of action of SJ-172550 in inhibiting the interaction of MDM4 and p53

PLoS One. 2012;7(6):e37518. doi: 10.1371/journal.pone.0037518. Epub 2012 Jun 4.


SJ-172550 (1) was previously discovered in a biochemical high throughput screen for inhibitors of the interaction of MDMX and p53 and characterized as a reversible inhibitor (J. Biol. Chem. 2010; 285:10786). Further study of the biochemical mode of action of 1 has shown that it acts through a complicated mechanism in which the compound forms a covalent but reversible complex with MDMX and locks MDMX into a conformation that is unable to bind p53. The relative stability of this complex is influenced by many factors including the reducing potential of the media, the presence of aggregates, and other factors that influence the conformational stability of the protein. This complex mechanism of action hinders the further development of compound 1 as a selective MDMX inhibitor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetates / chemistry
  • Acetates / pharmacology*
  • Amino Acid Sequence
  • Buffers
  • Cell Cycle Proteins
  • Humans
  • Inhibitory Concentration 50
  • Models, Biological
  • Molecular Sequence Data
  • Nuclear Proteins / chemistry
  • Nuclear Proteins / metabolism*
  • Peptides / metabolism
  • Pliability / drug effects
  • Protein Binding / drug effects
  • Protein Conformation
  • Protein Stability / drug effects
  • Proto-Oncogene Proteins / chemistry
  • Proto-Oncogene Proteins / metabolism*
  • Pyrazoles / chemistry
  • Pyrazoles / pharmacology*
  • Temperature
  • Tumor Suppressor Protein p53 / chemistry
  • Tumor Suppressor Protein p53 / metabolism*


  • Acetates
  • Buffers
  • Cell Cycle Proteins
  • MDM4 protein, human
  • Nuclear Proteins
  • Peptides
  • Proto-Oncogene Proteins
  • Pyrazoles
  • SJ 172550
  • Tumor Suppressor Protein p53