4EZM

Crystal structure of the human IgE-Fc(epsilon)3-4 bound to its B cell receptor derCD23


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.1 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.264 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Crystal structure of IgE bound to its B-cell receptor CD23 reveals a mechanism of reciprocal allosteric inhibition with high affinity receptor Fc{varepsilon}RI.

Dhaliwal, B.Yuan, D.Pang, M.O.Henry, A.J.Cain, K.Oxbrow, A.Fabiane, S.M.Beavil, A.J.McDonnell, J.M.Gould, H.J.Sutton, B.J.

(2012) Proc.Natl.Acad.Sci.USA 109: 12686-12691

  • DOI: 10.1073/pnas.1207278109

  • PubMed Abstract: 
  • The role of IgE in allergic disease mechanisms is performed principally through its interactions with two receptors, FcεRI on mast cells and basophils, and CD23 (FcεRII) on B cells. The former mediates allergic hypersensitivity, the latter regulates ...

    The role of IgE in allergic disease mechanisms is performed principally through its interactions with two receptors, FcεRI on mast cells and basophils, and CD23 (FcεRII) on B cells. The former mediates allergic hypersensitivity, the latter regulates IgE levels, and both receptors, also expressed on antigen-presenting cells, contribute to allergen uptake and presentation to the immune system. We have solved the crystal structure of the soluble lectin-like "head" domain of CD23 (derCD23) bound to a subfragment of IgE-Fc consisting of the dimer of Cε3 and Cε4 domains (Fcε3-4). One CD23 head binds to each heavy chain at the interface between the two domains, explaining the known 2:1 stoichiometry and suggesting mechanisms for cross-linking membrane-bound trimeric CD23 by IgE, or membrane IgE by soluble trimeric forms of CD23, both of which may contribute to the regulation of IgE synthesis by B cells. The two symmetrically located binding sites are distant from the single FcεRI binding site, which lies at the opposite ends of the Cε3 domains. Structural comparisons with both free IgE-Fc and its FcεRI complex reveal not only that the conformational changes in IgE-Fc required for CD23 binding are incompatible with FcεRI binding, but also that the converse is true. The two binding sites are allosterically linked. We demonstrate experimentally the reciprocal inhibition of CD23 and FcεRI binding in solution and suggest that the mutual exclusion of receptor binding allows IgE to function independently through its two receptors.


    Organizational Affiliation

    Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, United Kingdom.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Ig epsilon chain C region
A, B, C, D, E, F
223Homo sapiensMutation(s): 2 
Gene Names: IGHE
Find proteins for P01854 (Homo sapiens)
Go to UniProtKB:  P01854
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Low affinity immunoglobulin epsilon Fc receptor
G, H, I, J, K, L
143Homo sapiensMutation(s): 0 
Gene Names: FCER2 (CD23A, CLEC4J, FCE2, IGEBF)
Find proteins for P06734 (Homo sapiens)
Go to Gene View: FCER2
Go to UniProtKB:  P06734
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MAN
Query on MAN

Download SDF File 
Download CCD File 
A, B, C, D, E, F
ALPHA-D-MANNOSE
C6 H12 O6
WQZGKKKJIJFFOK-PQMKYFCFSA-N
 Ligand Interaction
BMA
Query on BMA

Download SDF File 
Download CCD File 
A, B, C, D, E, F
BETA-D-MANNOSE
C6 H12 O6
WQZGKKKJIJFFOK-RWOPYEJCSA-N
 Ligand Interaction
NAG
Query on NAG

Download SDF File 
Download CCD File 
A, B, C, D, E, F
N-ACETYL-D-GLUCOSAMINE
C8 H15 N O6
OVRNDRQMDRJTHS-FMDGEEDCSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.1 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.264 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 62.890α = 90.00
b = 110.750β = 90.00
c = 376.560γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data reduction
BUSTERrefinement
PHASESphasing
HKL-2000data scaling
HKL-2000data collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-07-18
    Type: Initial release
  • Version 1.1: 2012-08-01
    Type: Database references
  • Version 1.2: 2012-08-15
    Type: Database references