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 
  • R-Value Observed: 0.182 

wwPDB Validation   3D Report Full Report


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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
  • Primary Citation of Related Structures:  
    4RXZ

  • 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 inhibition and degradation, acting to prevent damaged cells from proliferating through induction of cell cycle arrest, DNA repair, senescence or apoptosis ...

    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

    Center for Translational Medicine, Xi'an Jiaotong University School of Life Science and Technology, Shaanxi, China.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Protein Mdm4A, C [auth B]85Homo sapiensMutation(s): 0 
Gene Names: MDM4MDMX
Find proteins for O15151 (Homo sapiens)
Explore O15151 
Go to UniProtKB:  O15151
NIH Common Fund Data Resources
PHAROS:  O15151
Protein Feature View
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  • Reference Sequence
  • Find similar proteins by:  Sequence   |   Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
12-MER PEPTIDE INHIBITORB [auth C], D12N/AMutation(s): 0 
Protein Feature View
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  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
PTR
Query on PTR
A, C [auth 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 
  • R-Value Observed: 0.182 
  • Space Group: P 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 28.613α = 103.32
b = 41.43β = 103.67
c = 45.618γ = 102.44
Software Package:
Software NamePurpose
HKL-2000data collection
PHASERphasing
REFMACrefinement
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

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