4RXZ

Crystal Structure of MDMX phosporylated Tyr99 in complex with a 12-mer peptide


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.55 Å
  • R-Value Free: 0.220 
  • R-Value Work: 0.180 

wwPDB Validation 3D Report Full Report


This is version 1.0 of the entry. See complete history

Literature

Structural basis of how stress-induced MDMX phosphorylation activates p53.

Chen, X.Gohain, N.Zhan, C.Lu, W.Y.Pazgier, M.Lu, W.

(2015) Oncogene --: --

  • DOI: 10.1038/onc.2015.255

  • PubMed Abstract: 
  • The tumor-suppressor protein p53 is tightly controlled in normal cells by its two negative regulators--the E3 ubiquitin ligase MDM2 and its homolog MDMX. Under stressed conditions such as DNA damage, p53 escapes MDM2- and MDMX-mediated functional inh ...

    The tumor-suppressor protein p53 is tightly controlled in normal cells by its two negative regulators--the E3 ubiquitin ligase MDM2 and its homolog MDMX. Under stressed conditions such as DNA damage, p53 escapes MDM2- and MDMX-mediated functional inhibition and degradation, acting to prevent damaged cells from proliferating through induction of cell cycle arrest, DNA repair, senescence or apoptosis. Ample evidence suggests that stress signals induce phosphorylation of MDM2 and MDMX, leading to p53 activation. However, the structural basis of stress-induced p53 activation remains poorly understood because of the paucity of technical means to produce site-specifically phosphorylated MDM2 and MDMX proteins for biochemical and biophysical studies. Herein, we report total chemical synthesis, via native chemical ligation, and functional characterization of (24-108)MDMX and its Tyr99-phosphorylated analog with respect to their ability to interact with a panel of p53-derived peptide ligands and PMI, a p53-mimicking but more potent peptide antagonist of MDMX, using FP and surface plasmon resonance techniques. Phosphorylation of MDMX at Tyr99 weakens peptide binding by approximately two orders of magnitude. Comparative X-ray crystallographic analyses of MDMX and of pTyr99 MDMX in complex with PMI as well as modeling studies reveal that the phosphate group of pTyr99 imposes extensive steric clashes with the C-terminus of PMI or p53 peptide and induces a significant lateral shift of the peptide ligand, contributing to the dramatic decrease in the binding affinity of MDMX for p53. Because DNA damage activates c-Abl tyrosine kinase that phosphorylates MDMX at Tyr99, our findings afford a rare glimpse at the structural level of how stress-induced MDMX phosphorylation dislodges p53 from the inhibitory complex and activates it in response to DNA damage.


    Organizational Affiliation

    Institute of Human Virology and Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Protein Mdm4
A, B
85Homo sapiensMutation(s): 0 
Gene Names: MDM4 (MDMX)
Find proteins for O15151 (Homo sapiens)
Go to Gene View: MDM4
Go to UniProtKB:  O15151
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
12-MER PEPTIDE INHIBITOR
C, D
12N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
PTR
Query on PTR
A, B
L-PEPTIDE LINKINGC9 H12 N O6 PTYR
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.55 Å
  • R-Value Free: 0.220 
  • R-Value Work: 0.180 
  • Space Group: P 1
Unit Cell:
Length (Å)Angle (°)
a = 28.613α = 103.32
b = 41.430β = 103.67
c = 45.618γ = 102.44
Software Package:
Software NamePurpose
HKL-2000data collection
HKL-2000data reduction
REFMACrefinement
HKL-2000data scaling
PHASERphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2015-07-22
    Type: Initial release