2IWL

Structure of the PX Domain of Phosphoinositide 3-Kinase-C2alpha


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.6 Å
  • R-Value Free: 0.290 
  • R-Value Work: 0.247 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural and Membrane Binding Analysis of the Phox Homology Domain of Phosphoinositide 3-Kinase- C2{Alpha}.

Stahelin, R.V.Karathanassis, D.Bruzik, K.S.Waterfield, M.D.Bravo, J.Williams, R.L.Cho, W.

(2006) J.Biol.Chem. 281: 39396

  • DOI: 10.1074/jbc.M607079200

  • PubMed Abstract: 
  • Phox homology (PX) domains, which have been identified in a variety of proteins involved in cell signaling and membrane trafficking, have been shown to interact with phosphoinositides (PIs) with different affinities and specificities. To elucidate th ...

    Phox homology (PX) domains, which have been identified in a variety of proteins involved in cell signaling and membrane trafficking, have been shown to interact with phosphoinositides (PIs) with different affinities and specificities. To elucidate the structural origin of diverse PI specificities of PX domains, we determined the crystal structure of the PX domain from phosphoinositide 3-kinase C2alpha (PI3K-C2alpha), which binds phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P(2)). To delineate the mechanism by which this PX domain interacts with membranes, we measured the membrane binding of the wild type domain and mutants by surface plasmon resonance and monolayer techniques. This PX domain contains a signature PI-binding site that is optimized for PtdIns(4,5)P(2) binding. The membrane binding of the PX domain is initiated by nonspecific electrostatic interactions followed by the membrane penetration of hydrophobic residues. Membrane penetration is specifically enhanced by PtdIns(4,5)P(2). Furthermore, the PX domain displayed significantly higher PtdIns(4,5)P(2) membrane affinity and specificity when compared with the PI3K-C2alpha C2 domain, demonstrating that high affinity PtdIns(4,5)P(2) binding was facilitated by the PX domain in full-length PI3K-C2alpha. Together, these studies provide new structural insight into the diverse PI specificities of PX domains and elucidate the mechanism by which the PI3K-C2alpha PX domain interacts with PtdIns(4,5)P(2)-containing membranes and thereby mediates the membrane recruitment of PI3K-C2alpha.


    Organizational Affiliation

    Departments of Chemistry and Medicinal Chemistry and Pharmacognosy, University of Illinois, Chicago, Illinois 60607, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
PHOSPHATIDYLINOSITOL-4-PHOSPHATE 3-KINASE C2 DOMAIN-CONTAINING ALPHA POLYPEPTIDE
X
140Homo sapiensMutation(s): 0 
Gene Names: PIK3C2A
EC: 2.7.1.154
Find proteins for O00443 (Homo sapiens)
Go to Gene View: PIK3C2A
Go to UniProtKB:  O00443
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
X
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.6 Å
  • R-Value Free: 0.290 
  • R-Value Work: 0.247 
  • Space Group: P 4 3 2
Unit Cell:
Length (Å)Angle (°)
a = 115.933α = 90.00
b = 115.933β = 90.00
c = 115.933γ = 90.00
Software Package:
Software NamePurpose
SCALAdata scaling
REFMACrefinement
MOSFLMdata reduction
autoSHARPphasing
TRUNCATEdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-10-18
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Advisory, Version format compliance
  • Version 1.2: 2018-01-24
    Type: Source and taxonomy