Crystallographic Refinement and Atomic Models of a Human FC Fragment and its Complex with Fragment B of Protein A from Staphylococcus Aureus at 2.9-and 2.8-Angstroms Resolution

Experimental Data Snapshot

  • Resolution: 2.80 Å

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Crystallographic refinement and atomic models of a human Fc fragment and its complex with fragment B of protein A from Staphylococcus aureus at 2.9- and 2.8-A resolution.

Deisenhofer, J.

(1981) Biochemistry 20: 2361-2370

  • Primary Citation of Related Structures:  
    1FC1, 1FC2

  • PubMed Abstract: 

    The model of human Fc fragment was refined at 2.9-A resolution. Two different automated procedures for crystallographic refinement were used [Deisenhofer, J., & Steigemann, W. (1975) Acta Crystallogr., Sec. B B31, 238; Jack, A., & Levitt, M. (1978) Acta Crystallogr., Sect. A A34, 931]. The final R value is 0.22. The dimer of CH3 domains closely resembles the CH1-CL aggregate in Fab fragments. There is no contact between CH2 domains. The contact between CH2 and CH3 domains has about one-third of the size of the CH3-CH3 contact. The carbohydrate, a branched chain of nine hexose units, covers parts of the C-contact face of the CH2 domain, shielding hydrophobic residues on this surface. Six atoms of the carbohydrate are within hydrogen-bonding distance of atoms in the CH2 domain. Crystallographic refinement of the complex between Fc fragment and fragment B of protein A from Staphylococcus aureus reduced the R value of the model is 0.24. A major part of the structure of fragment B consists of two alpha helics; the rest of the polypeptide chain is folded irregularly. In the crystal, fragment B forms two contacts with Fc fragment molecules. Contact 1 involves residues from both helices of fragment B, and residues from the CH2 and CH3 domains of FC, and is predominantly hydrophobic. Contact 2 is smaller than contact 1. Residues from the second helix and adjacent residues of fragment B and residues only from the CH3 domain of Fc contribute to contact 2. The nature of contact 2 is mainly polar and includes a sulfate ion. There are strong arguments that contact 1 is the fragment B-Fc contact formed in solution under physiological conditions, while contact 2 is a crystal contact.

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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
FRAGMENT B OF PROTEIN A COMPLEXA [auth C]58Staphylococcus aureus subsp. aureus NCTC 8325Mutation(s): 0 
Find proteins for P38507 (Staphylococcus aureus)
Explore P38507 
Go to UniProtKB:  P38507
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP38507
Sequence Annotations
  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
IMMUNOGLOBULIN FCB [auth D]224Homo 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
Sequence Annotations
  • Reference Sequence


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)]alpha-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-[alpha-L-fucopyranose-(1-6)]2-acetamido-2-deoxy-beta-D-glucopyranoseC [auth A]9N-Glycosylation
Glycosylation Resources
GlyTouCan:  G58978IW
GlyCosmos:  G58978IW
GlyGen:  G58978IW
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on SO4

Download Ideal Coordinates CCD File 
O4 S
Experimental Data & Validation

Experimental Data

  • Resolution: 2.80 Å
  • Space Group: P 31 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 70.6α = 90
b = 70.6β = 90
c = 147.4γ = 120

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1981-10-02
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Source and taxonomy, Version format compliance
  • Version 2.0: 2020-07-29
    Type: Remediation
    Reason: Carbohydrate remediation
    Changes: Advisory, Atomic model, Data collection, Database references, Derived calculations, Other, Structure summary
  • Version 3.0: 2020-12-16
    Changes: Atomic model, Data collection, Derived calculations, Structure summary