3FAY

Crystal structure of the GAP-related domain of IQGAP1


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.258 
  • R-Value Work: 0.228 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Crystal structure of the GTPase-activating protein-related domain from IQGAP1.

Kurella, V.B.Richard, J.M.Parke, C.L.Lecour, L.F.Bellamy, H.D.Worthylake, D.K.

(2009) J.Biol.Chem. 284: 14857-14865

  • DOI: 10.1074/jbc.M808974200

  • PubMed Abstract: 
  • IQGAP1 is a 190-kDa molecular scaffold containing several domains required for interaction with numerous proteins. One domain is homologous to Ras GTPase-activating protein (GAP) domains. However, instead of accelerating hydrolysis of bound GTP on Ra ...

    IQGAP1 is a 190-kDa molecular scaffold containing several domains required for interaction with numerous proteins. One domain is homologous to Ras GTPase-activating protein (GAP) domains. However, instead of accelerating hydrolysis of bound GTP on Ras IQGAP1, using its GAP-related domain (GRD) binds to Cdc42 and Rac1 and stabilizes their GTP-bound states. We report here the crystal structure of the isolated IQGAP1 GRD. Despite low sequence conservation, the overall structure of the GRD is very similar to the GAP domains from p120 RasGAP, neurofibromin, and SynGAP. However, instead of the catalytic "arginine finger" seen in functional Ras GAPs, the GRD has a conserved threonine residue. GRD residues 1099-1129 have no structural equivalent in RasGAP and are seen to form an extension at one end of the molecule. Because the sequence of these residues is highly conserved, this region likely confers a functionality particular to IQGAP family GRDs. We have used isothermal titration calorimetry to demonstrate that the isolated GRD binds to active Cdc42. Assuming a mode of interaction similar to that displayed in the Ras-RasGAP complex, we created an energy-minimized model of Cdc42.GTP bound to the GRD. Residues of the GRD that contact Cdc42 map to the surface of the GRD that displays the highest level of sequence conservation. The model indicates that steric clash between threonine 1046 with the phosphate-binding loop and other subtle changes would likely disrupt the proper geometry required for GTP hydrolysis.


    Organizational Affiliation

    Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Ras GTPase-activating-like protein IQGAP1
A
387Homo sapiensMutation(s): 0 
Gene Names: IQGAP1 (KIAA0051)
Find proteins for P46940 (Homo sapiens)
Go to Gene View: IQGAP1
Go to UniProtKB:  P46940
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
TRS
Query on TRS

Download SDF File 
Download CCD File 
A
2-AMINO-2-HYDROXYMETHYL-PROPANE-1,3-DIOL
TRIS BUFFER
C4 H12 N O3
LENZDBCJOHFCAS-UHFFFAOYSA-O
 Ligand Interaction
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: 2.2 Å
  • R-Value Free: 0.258 
  • R-Value Work: 0.228 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 170.133α = 90.00
b = 42.115β = 90.00
c = 59.382γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data collection
SHELXSphasing
HKL-2000data reduction
HKL-2000data scaling
CNSrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2009-03-24
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance