Crystal structure of the alpha-X beta2 integrin I domain

Experimental Data Snapshot

  • Resolution: 1.65 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.209 

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Structure and allosteric regulation of the alpha X beta 2 integrin I domain.

Vorup-Jensen, T.Ostermeier, C.Shimaoka, M.Hommel, U.Springer, T.A.

(2003) Proc Natl Acad Sci U S A 100: 1873-1878

  • DOI: https://doi.org/10.1073/pnas.0237387100
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The integrin alpha X beta 2 (CD11c/CD18, p150,95) binds ligands through the I domain of the alpha X subunit. Ligands include the complement factor fragment iC3b, a key component in the innate immune defense, which, together with the expression of alpha X beta 2 on dendritic cells and on other leukocytes, suggests a role in the immune response. We now report the structure of the alpha X I domain resolved at 1.65 A by x-ray crystallography. To analyze structural requirements for ligand binding we made a mutation in the alpha X I domain C-terminal helix, which increased the affinity for iC3b approximately 200-fold to 2.4 microM compared with the wild-type domain affinity of approximately 400 microM. Gel permeation chromatography supported a conformational change between the wild-type and mutated domains. Conservation of allosteric regulation in the alpha X I domain points to the functional importance of this phenomenon.

  • Organizational Affiliation

    Center for Blood Research, Department of Pathology, Harvard Medical School, 200 Longwood Avenue, Boston, MA 02115, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Integrin alpha-X198Homo sapiensMutation(s): 2 
Gene Names: ITGAX OR CD11C
UniProt & NIH Common Fund Data Resources
Find proteins for P20702 (Homo sapiens)
Explore P20702 
Go to UniProtKB:  P20702
GTEx:  ENSG00000140678 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP20702
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.65 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.208 
  • R-Value Observed: 0.209 
  • Space Group: P 61
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 84.694α = 90
b = 84.694β = 90
c = 65.776γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-02-18
    Type: Initial release
  • Version 1.1: 2008-04-28
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-10-27
    Changes: Database references
  • Version 1.4: 2024-02-14
    Changes: Data collection