1M1U

AN ISOLEUCINE-BASED ALLOSTERIC SWITCH CONTROLS AFFINITY AND SHAPE SHIFTING IN INTEGRIN CD11B A-DOMAIN

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.248 
  • R-Value Work: 0.188 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history. 


Literature

An isoleucine-based allosteric switch controls affinity and shape shifting in integrin CD11b A-domain.

Xiong, J.P., Li, R., Essafi, M., Stehle, T., Arnaout, M.A.

(2000) J Biol Chem 275: 38762-38767

  • DOI: 10.1074/jbc.C000563200
  • Primary Citation of Related Structures:  
    1M1U

  • PubMed Abstract: 

    • In response to cell activation signals, integrins switch from a low to a high affinity state. Physiologic ligands bind to integrins through a von Willebrand Factor A-type domain. Crystallographic studies revealed two conformations of this domain, "closed" and "open ...

    In response to cell activation signals, integrins switch from a low to a high affinity state. Physiologic ligands bind to integrins through a von Willebrand Factor A-type domain. Crystallographic studies revealed two conformations of this domain, "closed" and "open." The latter crystallizes in complex with a pseudoligand or ligand, suggesting that it represents the high affinity state; data linking structure and activity are lacking however. In this communication, we expressed stable low and high affinity forms of integrin CD11b A-domain and determined their binding isotherms and crystal structures. The low affinity form, generated by deleting an N-terminal extension extrinsic to the domain, did not bind to physiologic ligands, and crystallized in the closed conformation. The high affinity form was generated by either deleting or substituting an invariable C-terminal Ile(316), wedged into a hydrophobic socket in the closed form, but displaced from it in the open structure. Both mutants crystallized in the open conformation, and the Ile(316) --> Gly-modified integrin displayed high affinity. Structural differences between the low and high affinity forms were detected in solution. These data establish the structure-function correlates for the CD11b A-domain, and define a ligand-independent isoleucine-based allosteric switch intrinsic to this domain that controls its conformation and affinity.

    Organizational Affiliation: 

    Leukocyte Biology and Inflammation Program, Renal Unit, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129, USA.



Macromolecules
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(by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Integrin alpha-M A195Homo sapiensMutation(s): 1 
Gene Names: ITGAM, CD11B, CR3A
Find proteins for P11215 (Homo sapiens)
Explore P11215 
Go to UniProtKB:  P11215
NIH Common Fund Data Resources
PHAROS:  P11215
GTEx:  ENSG00000169896
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA
Download Ideal Coordinates CCD File 
A
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N		 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.30 Å
  • R-Value Free: 0.248 
  • R-Value Work: 0.188 
  • Space Group: P 43
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 45.7α = 90
b = 45.7β = 90
c = 94.8γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
DENZOdata reduction
SCALEPACKdata scaling
X-PLORphasing

Structure Validation

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View more in-depth experimental data

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2002-08-07
    Type: Initial release
  • Version 1.1: 2008-04-28
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance