4C55

Crystal structure of serum-derived human IgG4 Fc


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.190 

wwPDB Validation   3D Report Full Report


This is version 2.1 of the entry. See complete history


Literature

Structural Determinants of Unique Properties of Human Igg4-Fc

Davies, A.M.Rispens, T.Ooijevaar-Deheer, P.Gould, H.J.Jefferis, R.Aalberse, R.C.Sutton, B.J.

(2014) J Mol Biol 426: 630

  • DOI: https://doi.org/10.1016/j.jmb.2013.10.039
  • Primary Citation of Related Structures:  
    4C54, 4C55

  • PubMed Abstract: 

    Human IgG4, normally the least abundant of the four subclasses of IgG in serum, displays a number of unique biological properties. It can undergo heavy-chain exchange, also known as Fab-arm exchange, leading to the formation of monovalent but bispecific antibodies, and it interacts poorly with FcγRII and FcγRIII, and complement. These properties render IgG4 relatively "non-inflammatory" and have made it a suitable format for therapeutic monoclonal antibody production. However, IgG4 is also known to undergo Fc-mediated aggregation and has been implicated in auto-immune disease pathology. We report here the high-resolution crystal structures, at 1.9 and 2.35 Å, respectively, of human recombinant and serum-derived IgG4-Fc. These structures reveal conformational variability at the CH3-CH3 interface that may promote Fab-arm exchange, and a unique conformation for the FG loop in the CH2 domain that would explain the poor FcγRII, FcγRIII and C1q binding properties of IgG4 compared with IgG1 and -3. In contrast to other IgG subclasses, this unique conformation folds the FG loop away from the CH2 domain, precluding any interaction with the lower hinge region, which may further facilitate Fab-arm exchange by destabilisation of the hinge. The crystals of IgG4-Fc also display Fc-Fc packing contacts with very extensive interaction surfaces, involving both a consensus binding site in IgG-Fc at the CH2-CH3 interface and known hydrophobic aggregation motifs. These Fc-Fc interactions are compatible with intact IgG4 molecules and may provide a model for the formation of aggregates of IgG4 that can cause disease pathology in the absence of antigen.


  • Organizational Affiliation

    Randall Division of Cell and Molecular Biophysics, King's College London, London SE1 1UL, United Kingdom; Medical Research Council and Asthma UK Centre in Allergic Mechanisms of Asthma, London SE1 9RT, United Kingdom. Electronic address: anna.davies@kcl.ac.uk.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
IG GAMMA-4 CHAIN C REGION
A, B
218Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P01861 (Homo sapiens)
Explore P01861 
Go to UniProtKB:  P01861
PHAROS:  P01861
GTEx:  ENSG00000211892 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP01861
Sequence Annotations
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  • Reference Sequence
Oligosaccharides

Help

Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
beta-D-galactopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-2)-alpha-D-mannopyranose-(1-6)-[2-acetamido-2-deoxy-beta-D-glucopyranose-(1-2)-alpha-D-mannopyranose-(1-3)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-[alpha-L-fucopyranose-(1-6)]2-acetamido-2-deoxy-beta-D-glucopyranose
C
9N-Glycosylation
Glycosylation Resources
GlyTouCan:  G27919IH
GlyCosmos:  G27919IH
GlyGen:  G27919IH
Entity ID: 3
MoleculeChains Length2D Diagram Glycosylation3D Interactions
beta-D-galactopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-2)-alpha-D-mannopyranose-(1-6)-[2-acetamido-2-deoxy-beta-D-glucopyranose-(1-2)-alpha-D-mannopyranose-(1-3)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose
D
8N-Glycosylation
Glycosylation Resources
GlyTouCan:  G89993FE
GlyCosmos:  G89993FE
GlyGen:  G89993FE
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.188 
  • R-Value Observed: 0.190 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 74.298α = 90
b = 80.738β = 90
c = 99.19γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
Aimlessdata scaling
MOLREPphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-11-13
    Type: Initial release
  • Version 1.1: 2013-11-20
    Changes: Database references
  • Version 1.2: 2014-02-05
    Changes: Database references
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Derived calculations, Other, Structure summary
  • Version 2.1: 2023-12-20
    Changes: Data collection, Database references, Refinement description, Structure summary