3D3V

The complex between TCR A6 and human Class I MHC HLA-A2 with the modified HTLV-1 TAX (Y5(3,4-difluoroPhenylalanine)) peptide


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.220 

Starting Model: experimental
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wwPDB Validation   3D Report Full Report


This is version 1.4 of the entry. See complete history


Literature

Fluorine substitutions in an antigenic peptide selectively modulate T-cell receptor binding in a minimally perturbing manner.

Piepenbrink, K.H.Borbulevych, O.Y.Sommese, R.F.Clemens, J.Armstrong, K.M.Desmond, C.Do, P.Baker, B.M.

(2009) Biochem J 423: 353-361

  • DOI: https://doi.org/10.1042/BJ20090732
  • Primary Citation of Related Structures:  
    3D39, 3D3V

  • PubMed Abstract: 

    TCR (T-cell receptor) recognition of antigenic peptides bound and presented by MHC (major histocompatibility complex) molecules forms the basis of the cellular immune response to pathogens and cancer. TCRs bind peptide-MHC complexes weakly and with fast kinetics, features which have hindered detailed biophysical studies of these interactions. Modified peptides resulting in enhanced TCR binding could help overcome these challenges. Furthermore, there is considerable interest in using modified peptides with enhanced TCR binding as the basis for clinical vaccines. In the present study, we examined how fluorine substitutions in an antigenic peptide can selectively impact TCR recognition. Using a structure-guided design approach, we found that fluorination of the Tax peptide [HTLV (human T-cell lymphotropic virus)-1 Tax(11-19)] enhanced binding by the Tax-specific TCR A6, yet weakened binding by the Tax-specific TCR B7. The changes in affinity were consistent with crystallographic structures and fluorine chemistry, and with the A6 TCR independent of other substitutions in the interface. Peptide fluorination thus provides a means to selectively modulate TCR binding affinity without significantly perturbing peptide composition or structure. Lastly, we probed the mechanism of fluorine's effect on TCR binding and we conclude that our results were most consistent with a 'polar hydrophobicity' mechanism, rather than a purely hydrophobic- or electrostatic-based mechanism. This finding should have an impact on other attempts to alter molecular recognition with fluorine.


  • Organizational Affiliation

    Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN 46556, USA.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
HLA class I histocompatibility antigen, A-2 alpha chain275Homo sapiensMutation(s): 0 
Gene Names: HLA-AHLAA
UniProt & NIH Common Fund Data Resources
Find proteins for P04439 (Homo sapiens)
Explore P04439 
Go to UniProtKB:  P04439
PHAROS:  P04439
GTEx:  ENSG00000206503 
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UniProt GroupP04439
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  • Reference Sequence
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Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Beta-2-microglobulin100Homo sapiensMutation(s): 0 
Gene Names: B2MCDABP0092HDCMA22P
UniProt & NIH Common Fund Data Resources
Find proteins for P61769 (Homo sapiens)
Explore P61769 
Go to UniProtKB:  P61769
PHAROS:  P61769
GTEx:  ENSG00000166710 
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UniProt GroupP61769
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  • Reference Sequence

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Entity ID: 3
MoleculeChains Sequence LengthOrganismDetailsImage
Modified HTLV-1 TAX (Y5(3,4-difluoro)F) peptide9N/AMutation(s): 0 
Sequence Annotations
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  • Reference Sequence
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Entity ID: 4
MoleculeChains Sequence LengthOrganismDetailsImage
A6 TCR alpha chain200Homo sapiensMutation(s): 0 
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  • Reference Sequence
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Entity ID: 5
MoleculeChains Sequence LengthOrganismDetailsImage
A6 TCR beta chain245Homo sapiensMutation(s): 0 
UniProt
Find proteins for P01850 (Homo sapiens)
Explore P01850 
Go to UniProtKB:  P01850
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UniProt GroupP01850
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.220 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 224.45α = 90
b = 48.537β = 90.61
c = 93.794γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
SBC-Collectdata collection
HKL-2000data reduction
HKL-2000data scaling
MOLREPphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-06-16
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.2: 2015-01-21
    Changes: Database references
  • Version 1.3: 2023-08-30
    Changes: Data collection, Database references, Derived calculations, Refinement description
  • Version 1.4: 2023-11-15
    Changes: Data collection