2W6B

Crystal Structure of the Trimeric beta-PIX Coiled-Coil Domain


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.8 Å
  • R-Value Free: 0.305 
  • R-Value Work: 0.278 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structures of Dimeric Git1 and Trimeric Beta-Pix and Implications for Git-Pix Complex Assembly.

Schlenker, O.Rittinger, K.

(2009) J.Mol.Biol. 386: 280

  • DOI: 10.1016/j.jmb.2008.12.050
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • GIT (G protein-coupled receptor kinase-interacting protein) and PIX (p21-activated kinase-interacting exchange factor) family proteins integrate signaling pathways involving Arf and Rho family GTPases. GIT1 and beta-PIX form a constitutively associat ...

    GIT (G protein-coupled receptor kinase-interacting protein) and PIX (p21-activated kinase-interacting exchange factor) family proteins integrate signaling pathways involving Arf and Rho family GTPases. GIT1 and beta-PIX form a constitutively associated complex that acts as a scaffold to allow the formation of large multiprotein assemblies that regulate synaptogenesis, cell polarity and cell migration among other physiological processes. Complex formation is mediated by the GIT binding domain (GBD) in beta-PIX, which recognizes the Spa homology domain of GIT1. Both binding domains are adjacent to predicted coiled-coil segments that allow homo-oligomerization of GIT1 and beta-PIX, respectively. Oligomerization of GIT and PIX proteins is important for their physiological functions, and deletion of the coiled-coil domains interferes with correct subcellular localization and the GEF (guanine nucleotide exchange factor) activity of PIX. We have solved the crystal structures of the CC domains of GIT1 and beta-PIX and determined the stoichiometry of complex formation between the two proteins in order to understand the molecular architecture of the GIT1-beta-PIX complex. The crystal structure of the CC domain of GIT1 solved at 1.4 A resolution shows a dimeric, parallel CC that spans 67 A in length. Unexpectedly, and in contrast to prevalent dimeric models, the structure of the CC region of beta-PIX determined at 2.8 A resolution, combined with hydrodynamic studies, reveals that this protein forms a parallel trimer. Furthermore, we demonstrate that dimeric GIT and trimeric PIX form an unusual high-affinity heteropentameric complex in which each Spa homology domain of the GIT1 dimer recognizes one GBD of the beta-PIX trimer, leaving one GBD unoccupied. These results can serve as a basis to better understand oligomerization-dependent GIT1-beta-PIX-regulated signaling events and provide an insight into the architecture of large signaling complexes involving GIT1 and beta-PIX.


    Organizational Affiliation

    Medical Research Council National Institute for Medical Research, The Ridgeway, London, UK.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
RHO GUANINE NUCLEOTIDE EXCHANGE FACTOR 7
A
56Rattus norvegicusMutation(s): 0 
Gene Names: Arhgef7 (Pak3bp, Pixb)
Find proteins for O55043 (Rattus norvegicus)
Go to UniProtKB:  O55043
Small Molecules
Modified Residues  1 Unique
IDChainsTypeFormula2D DiagramParent
MSE
Query on MSE
A
L-PEPTIDE LINKINGC5 H11 N O2 SeMET
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.8 Å
  • R-Value Free: 0.305 
  • R-Value Work: 0.278 
  • Space Group: P 63
Unit Cell:
Length (Å)Angle (°)
a = 43.120α = 90.00
b = 43.120β = 90.00
c = 79.430γ = 120.00
Software Package:
Software NamePurpose
PHASERphasing
DENZOdata reduction
REFMACrefinement
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2009-01-20
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance