Experimental Data Snapshot

  • Resolution: 2.90 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.246 
  • R-Value Observed: 0.251 

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This is version 1.5 of the entry. See complete history


Design, characterization, and structure of a biologically active single-chain mutant of human IFN-gamma.

Landar, A.Curry, B.Parker, M.H.DiGiacomo, R.Indelicato, S.R.Nagabhushan, T.L.Rizzi, G.Walter, M.R.

(2000) J Mol Biol 299: 169-179

  • DOI: https://doi.org/10.1006/jmbi.2000.3734
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    A mutant form of human interferon-gamma (IFN-gamma SC1) that binds one IFN-gamma receptor alpha chain (IFN-gamma R alpha) has been designed and characterized. IFN-gamma SC1 was derived by linking the two peptide chains of the IFN-gamma dimer by a seven-residue linker and changing His111 in the first chain to an aspartic acid residue. Isothermal titration calorimetry shows that IFN-gamma SC1 forms a 1:1 complex with its high-affinity receptor (IFN-gamma R alpha) with an affinity of 27(+/- 9) nM. The crystal structure of IFN-gamma SC1 has been determined at 2.9 A resolution from crystals grown in 1.4 M citrate solutions at pH 7.6. Comparison of the wild-type receptor-binding domain and the Asp111-containing domain of IFN-gamma SC1 show that they are structurally equivalent but have very different electrostatic surface potentials. As a result, surface charge rather than structural changes is likely responsible for the inability of the His111-->Asp domain of to bind IFN-gamma R alpha. The AB loops of IFN-gamma SC1 adopt conformations similar to the ordered loops of IFN-gamma observed in the crystal structure of the IFN-gamma/IFN-gamma R alpha complex. Thus, IFN-gamma R alpha binding does not result in a large conformational change in the AB loop as previously suggested. The structure also reveals the final six C-terminal amino acid residues of IFN-gamma SC1 (residues 253-258) that have not been observed in any other reported IFN-gamma structures. Despite binding to only one IFN-gamma R alpha, IFN-gamma SC1 is biologically active in cell proliferation, MHC class I induction, and anti-viral assays. This suggests that one domain of IFN-gamma is sufficient to recruit IFN-gamma R alpha and IFN-gamma R beta into a complex competent for eliciting biological activity. The current data are consistent with the main role of the IFN-gamma dimer being to decrease the dissociation constant of IFN-gamma for its cellular receptors.

  • Organizational Affiliation

    Center for Macromolecular Crystallography, University of Alabama, Birmingham 35294, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Interferon gamma
A, B
265Homo sapiensMutation(s): 2 
Gene Names: IFNG
UniProt & NIH Common Fund Data Resources
Find proteins for P01579 (Homo sapiens)
Explore P01579 
Go to UniProtKB:  P01579
PHAROS:  P01579
GTEx:  ENSG00000111537 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP01579
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.90 Å
  • R-Value Free: 0.265 
  • R-Value Work: 0.246 
  • R-Value Observed: 0.251 
  • Space Group: H 3 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 111.38α = 90
b = 111.38β = 90
c = 311.96γ = 120
Software Package:
Software NamePurpose
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2000-09-01
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-06-14
    Changes: Database references, Source and taxonomy, Structure summary
  • Version 1.4: 2017-10-04
    Changes: Refinement description
  • Version 1.5: 2024-02-07
    Changes: Data collection, Database references, Derived calculations