1H3U

CRYSTAL STRUCTURE OF THE HUMAN IGG1 FC-FRAGMENT,GLYCOFORM (M3N2F)2


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.289 
  • R-Value Work: 0.253 
  • R-Value Observed: 0.253 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 2.1 of the entry. See complete history


Literature

Structural Analysis of Human Igg-Fc Glycoforms Reveals a Correlation between Glycosylation and Structural Integrity.

Krapp, S.Mimura, Y.Jefferis, R.Huber, R.Sondermann, P.

(2003) J Mol Biol 325: 979

  • DOI: https://doi.org/10.1016/s0022-2836(02)01250-0
  • Primary Citation of Related Structures:  
    1H3T, 1H3U, 1H3V, 1H3W, 1H3X, 1H3Y

  • PubMed Abstract: 

    Antibodies may be viewed as adaptor molecules that provide a link between humoral and cellular defence mechanisms. Thus, when antigen-specific IgG antibodies form antigen/antibody immune complexes the effectively aggregated IgG can activate a wide range of effector systems. Multiple effector mechanisms result from cellular activation mediated through a family of IgG-Fc receptors differentially expressed on leucocytes. It is established that glycosylation of IgG-Fc is essential for recognition and activation of these ligands. IgG antibodies predominate in human serum and most therapeutic antibodies are of the IgG class. The IgG-Fc is a homodimer of N-linked glycopeptide chains comprised of two immunoglobulin domains (Cgamma2, Cgamma3) that dimerise via inter-heavy chain disulphide bridges at the N-terminal region and non-covalent interactions between the C-terminal Cgamma3 domains. The overall shape of the IgG-Fc is similar to that of a "horseshoe" with a majority of the internal space filled by the oligosaccharide chains, only attached through asparagine residues 297.To investigate the influence of individual sugar (monosaccharide) residues of the oligosaccharide on the structure and function of IgG-Fc we have compared the structure of "wild-type" glycosylated IgG1-Fc with that of four glycoforms bearing consecutively truncated oligosaccharides. Removal of terminal N-acetylglucosamine as well as mannose sugar residues resulted in the largest conformational changes in both the oligosaccharide and in the polypeptide loop containing the N-glycosylation site. The observed conformational changes in the Cgamma2 domain affect the interface between IgG-Fc fragments and FcgammaRs. Furthermore, we observed that the removal of sugar residues permits the mutual approach of Cgamma2 domains resulting in the generation of a "closed" conformation; in contrast to the "open" conformation which was observed for the fully galactosylated IgG-Fc, which may be optimal for FcgammaR binding. These data provide a structural rationale for the previously observed modulation of effector activities reported for this series of proteins.


  • Organizational Affiliation

    Max-Planck-Institut für Biochemie, Abteilung Strukturforschung, Am Klopferspitz 18a, D-82152, Martinsried, Germany.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
IG GAMMA-1 CHAIN C REGION
A, B
223Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P01857 (Homo sapiens)
Explore P01857 
Go to UniProtKB:  P01857
PHAROS:  P01857
GTEx:  ENSG00000211896 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP01857
Glycosylation
Glycosylation Sites: 1Go to GlyGen: P01857-2
Sequence Annotations
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  • Reference Sequence
Oligosaccharides

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Entity ID: 2
MoleculeChains Length2D Diagram Glycosylation3D Interactions
alpha-D-mannopyranose-(1-3)-[alpha-D-mannopyranose-(1-6)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-[beta-L-fucopyranose-(1-6)]2-acetamido-2-deoxy-beta-D-glucopyranose
C
6N-Glycosylation
Glycosylation Resources
GlyTouCan:  G31616YD
GlyCosmos:  G31616YD
GlyGen:  G31616YD
Entity ID: 3
MoleculeChains Length2D Diagram Glycosylation3D Interactions
beta-D-mannopyranose-(1-3)-[alpha-D-mannopyranose-(1-6)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-[beta-L-fucopyranose-(1-6)]2-acetamido-2-deoxy-beta-D-glucopyranose
D
6N-Glycosylation
Glycosylation Resources
GlyTouCan:  G84914ZF
GlyCosmos:  G84914ZF
GlyGen:  G84914ZF
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.40 Å
  • R-Value Free: 0.289 
  • R-Value Work: 0.253 
  • R-Value Observed: 0.253 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 49.48α = 90
b = 79.63β = 90
c = 143.86γ = 90
Software Package:
Software NamePurpose
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling
AMoREphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2003-01-23
    Type: Initial release
  • Version 1.1: 2011-10-19
    Changes: Derived calculations, Non-polymer description, Other, Refinement description, Version format compliance
  • 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: 2023-12-13
    Changes: Data collection, Database references, Refinement description, Structure summary