4TV3

Isolated p110a subunit of PI3Ka provides a platform for structure-based drug design


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.85 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.210 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Engineering of an isolated p110 alpha subunit of PI3K alpha permits crystallization and provides a platform for structure-based drug design.

Chen, P.Deng, Y.L.Bergqvist, S.Falk, M.D.Liu, W.Timofeevski, S.Brooun, A.

(2014) Protein Sci 23: 1332-1340

  • DOI: 10.1002/pro.2517
  • Primary Citation of Related Structures:  
    4TV3, 4TUU

  • PubMed Abstract: 
  • PI3Kα remains an attractive target for the development of anticancer targeted therapy. A number of p110α crystal structures in complex with the nSH2-iSH2 fragment of p85 regulatory subunit have been reported, including a few small molecule co-crystal str ...

    PI3Kα remains an attractive target for the development of anticancer targeted therapy. A number of p110α crystal structures in complex with the nSH2-iSH2 fragment of p85 regulatory subunit have been reported, including a few small molecule co-crystal structures, but the utilization of this crystal form is limited by low diffraction resolution and a crystal packing artifact that partially blocks the ATP binding site. Taking advantage of recent data on the functional characterization of the lipid binding properties of p110α, we designed a set of novel constructs allowing production of isolated stable p110α subunit missing the Adapter Binding Domain and lacking or featuring a modified C-terminal lipid binding motif. While this protein is not catalytically competent to phosphorylate its substrate PIP2, it retains ligand binding properties as indicated by direct binding studies with a pan-PI3Kα inhibitor. Additionally, we determined apo and PF-04691502 bound crystal structures of the p110α (105-1048) subunit at 2.65 and 2.85 Å, respectively. Comparison of isolated p110α(105-1048) with the p110α/p85 complex reveals a high degree of structural similarity, which validates suitability of this catalytically inactive p110α for iterative SBDD. Importantly, this crystal form of p110α readily accommodates the binding of noncovalent inhibitor by means of a fully accessible ATP site. The strategy presented here can be also applied to structural studies of other members of PI3KIA family.


    Organizational Affiliation

    Oncology Structural Biology, Worldwide Research and Development, Pfizer Inc., San Diego, California, 92121.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit alpha isoform A946Homo sapiensMutation(s): 0 
Gene Names: PIK3CA
EC: 2.7.1.153 (PDB Primary Data), 2.7.11.1 (PDB Primary Data)
Find proteins for P42336 (Homo sapiens)
Explore P42336 
Go to UniProtKB:  P42336
NIH Common Fund Data Resources
PHAROS:  P42336
Protein Feature View
Expand
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ML9
Query on ML9

Download Ideal Coordinates CCD File 
A
2-amino-8-[trans-4-(2-hydroxyethoxy)cyclohexyl]-6-(6-methoxypyridin-3-yl)-4-methylpyrido[2,3-d]pyrimidin-7(8H)-one
C22 H27 N5 O4
XDLYKKIQACFMJG-WKILWMFISA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
ML9Ki:  0.5699999928474426   nM  BindingDB
ML9IC50:  3.299999952316284   nM  BindingDB
ML9Ki:  0.5699999928474426   nM  BindingDB
ML9IC50:  8.300000190734863   nM  BindingDB
ML9IC50:  4.849999904632568   nM  BindingDB
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.85 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.210 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 58.038α = 90
b = 136.773β = 90
c = 142.644γ = 90
Software Package:
Software NamePurpose
BUSTERrefinement

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2014-08-06
    Type: Initial release
  • Version 1.1: 2014-10-01
    Changes: Database references
  • Version 1.2: 2015-02-04
    Changes: Derived calculations