1FCC

CRYSTAL STRUCTURE OF THE C2 FRAGMENT OF STREPTOCOCCAL PROTEIN G IN COMPLEX WITH THE FC DOMAIN OF HUMAN IGG


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.20 Å
  • R-Value Free: 0.357 
  • R-Value Work: 0.289 
  • R-Value Observed: 0.289 

wwPDB Validation   3D Report Full Report


This is version 1.4 of the entry. See complete history


Literature

Crystal structure of the C2 fragment of streptococcal protein G in complex with the Fc domain of human IgG.

Sauer-Eriksson, A.E.Kleywegt, G.J.Uhlen, M.Jones, T.A.

(1995) Structure 3: 265-278

  • DOI: https://doi.org/10.1016/s0969-2126(01)00157-5
  • Primary Citation of Related Structures:  
    1FCC

  • PubMed Abstract: 

    Streptococcal protein G comprises two or three domains that bind to the constant Fc region of most mammalian immunoglobulin Gs (IgGs). Protein G is functionally related to staphylococcal protein A, with which it shares neither sequence nor structural homology. To understand the competitive binding of these two proteins to the Fc region, the crystal structure of a single Ig-binding domain of streptococcal protein G was determined at 3.5 A resolution in complex with the Fc fragment of human IgG and compared with the structures of protein A:Fc and protein G:Fab complexes. Protein G binds to the interface between the second and third heavy chain constant domains of Fc, which is roughly the same binding site used by protein A. Protein G comprises one alpha-helix packed onto a four-stranded beta-sheet. Residues from protein G that are involved in binding are situated within the C-terminal part of the alpha-helix, the N-terminal part of the third beta-strand and the loop region connecting these two structural elements. The identified Fc-binding region of protein G agrees well with both biochemical and NMR spectroscopic data. However, the Fc-binding helices of protein G and protein A are not superimposable. Protein G and protein A have developed different strategies for binding to Fc. The protein G:Fc complex involves mainly charged and polar contacts, whereas protein A and Fc are held together through non-specific hydrophobic interactions and a few polar interactions. Several residues of Fc are involved in both the protein G:Fc and the protein A:Fc interaction, which explains the competitive binding of the two proteins. The apparent differences in their Fc-binding activities result from additional unique interactions.


  • Organizational Affiliation

    Department of Molecular Biology, Uppsala University, Sweden.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
IGG1 MO61 FCA,
C [auth B]
206Homo sapiensMutation(s): 0 
Gene Names: N-TERMINAL FRAGMENT OF
UniProt & NIH Common Fund Data Resources
Find proteins for P01857 (Homo sapiens)
Go to UniProtKB:  P01857
PHAROS:  P01857
GTEx:  ENSG00000211896 
Sequence Annotations
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
STREPTOCOCCAL PROTEIN G (C2 FRAGMENT)B [auth C],
D
56StreptococcusMutation(s): 0 
Gene Names: N-TERMINAL FRAGMENT OF
UniProt
Find proteins for P19909 (Streptococcus sp. group G)
Go to UniProtKB:  P19909
Sequence Annotations
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3.20 Å
  • R-Value Free: 0.357 
  • R-Value Work: 0.289 
  • R-Value Observed: 0.289 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 110.6α = 90
b = 110.6β = 90
c = 160.3γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
X-PLORphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1995-04-20
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2024-06-05
    Changes: Data collection, Database references, Other
  • Version 1.4: 2024-10-16
    Changes: Structure summary