4A0Q

Activated Conformation of Integrin alpha1 I-Domain mutant


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.184 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Structure of Collagen Receptor Integrin Aplha1I Domain Carrying the Activating Mutation E317A.

Lahti, M.Bligt, E.Niskanen, H.Parkash, V.Brandt, A.M.Jokinen, J.Patrikainen, P.Kapyla, J.Heino, J.Salminen, T.A.

(2011) J.Biol.Chem. 286: 43343

  • DOI: 10.1074/jbc.M111.261909

  • PubMed Abstract: 
  • We have analyzed the structure and function of the integrin α(1)I domain harboring a gain-of-function mutation E317A. To promote protein crystallization, a double variant with an additional C139S mutation was used. In cell adhesion assays, the E317A ...

    We have analyzed the structure and function of the integrin α(1)I domain harboring a gain-of-function mutation E317A. To promote protein crystallization, a double variant with an additional C139S mutation was used. In cell adhesion assays, the E317A mutation promoted binding to collagen. Similarly, the double mutation C139S/E317A increased adhesion compared with C139S alone. Furthermore, soluble α(1)I C139S/E317A was a higher avidity collagen binder than α(1)I C139S, indicating that the double variant represents an activated form. The crystal structure of the activated variant of α(1)I was solved at 1.9 Å resolution. The E317A mutation results in the unwinding of the αC helix, but the metal ion has moved toward loop 1, instead of loop 2 in the open α(2)I. Furthermore, unlike in the closed αI domains, the metal ion is pentacoordinated and, thus, prepared for ligand binding. Helix 7, which has moved downward in the open α(2)I structure, has not changed its position in the activated α(1)I variant. During the integrin activation, Glu(335) on helix 7 binds to the metal ion at the metal ion-dependent adhesion site (MIDAS) of the β(1) subunit. Interestingly, in our cell adhesion assays E317A could activate collagen binding even after mutating Glu(335). This indicates that the stabilization of helix 7 into its downward position is not required if the α(1) MIDAS is already open. To conclude, the activated α(1)I domain represents a novel conformation of the αI domain, mimicking the structural state where the Arg(287)-Glu(317) ion pair has just broken during the integrin activation.


    Organizational Affiliation

    Department of Biochemistry and Food Chemistry, University of Turku, Turku FI-20014, Finland.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
INTEGRIN ALPHA-1
A, B
201Homo sapiensMutation(s): 2 
Gene Names: ITGA1
Find proteins for P56199 (Homo sapiens)
Go to Gene View: ITGA1
Go to UniProtKB:  P56199
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MG
Query on MG

Download SDF File 
Download CCD File 
A, B
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.229 
  • R-Value Work: 0.184 
  • Space Group: P 3
Unit Cell:
Length (Å)Angle (°)
a = 95.470α = 90.00
b = 95.470β = 90.00
c = 37.719γ = 120.00
Software Package:
Software NamePurpose
XDSdata reduction
SCALEPACKdata scaling
MOLREPphasing
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-10-26
    Type: Initial release
  • Version 1.1: 2011-12-28
    Type: Other