2AV7

Crystal structure of HTLV-1 TAX peptide Bound to Human Class I MHC HLA-A2 with the K66A mutation in the heavy chain.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.05 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.171 

wwPDB Validation 3D Report Full Report


This is version 1.4 of the entry. See complete history

Literature

Unraveling a Hotspot for TCR Recognition on HLA-A2: Evidence Against the Existence of Peptide-independent TCR Binding Determinants.

Gagnon, S.J.Borbulevych, O.Y.Davis-Harrison, R.L.Baxter, T.K.Clemens, J.R.Armstrong, K.M.Turner, R.V.Damirjian, M.Biddison, W.E.Baker, B.M.

(2005) J.Mol.Biol. 353: 556-573

  • DOI: 10.1016/j.jmb.2005.08.024
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • T cell receptor (TCR) recognition of peptide takes place in the context of the major histocompatibility complex (MHC) molecule, which accounts for approximately two-thirds of the peptide/MHC buried surface. Using the class I MHC HLA-A2 and a large pa ...

    T cell receptor (TCR) recognition of peptide takes place in the context of the major histocompatibility complex (MHC) molecule, which accounts for approximately two-thirds of the peptide/MHC buried surface. Using the class I MHC HLA-A2 and a large panel of mutants, we have previously shown that surface mutations that disrupt TCR recognition vary with the identity of the peptide. The single exception is Lys66 on the HLA-A2 alpha1 helix, which when mutated to alanine disrupts recognition for 93% of over 250 different T cell clones or lines, independent of which peptide is bound. Thus, Lys66 could serve as a peptide-independent TCR binding determinant. Here, we have examined the role of Lys66 in TCR recognition of HLA-A2 in detail. The structure of a peptide/HLA-A2 molecule with the K66A mutation indicates that although the mutation induces no major structural changes, it results in the exposure of a negatively charged glutamate (Glu63) underneath Lys66. Concurrent replacement of Glu63 with glutamine restores TCR binding and function for T cells specific for five different peptides presented by HLA-A2. Thus, the positive charge on Lys66 does not serve to guide all TCRs onto the HLA-A2 molecule in a manner required for productive signaling. Furthermore, electrostatic calculations indicate that Lys66 does not contribute to the stability of two TCR-peptide/HLA-A2 complexes. Our findings are consistent with the notion that each TCR arrives at a unique solution of how to bind a peptide/MHC, most strongly influenced by the chemical and structural features of the bound peptide. This would not rule out an intrinsic affinity of TCRs for MHC molecules achieved through multiple weak interactions, but for HLA-A2 the collective mutational data place limits on the role of any single MHC amino acid side-chain in driving TCR binding in a peptide-independent fashion.


    Organizational Affiliation

    Molecular Immunology Section, Neuroimmunology Branch, National Institute of Neurological Diseases and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
HLA class I histocompatibility antigen, A-2 alpha chain
A, D
275Homo sapiensMutation(s): 1 
Gene Names: HLA-A (HLAA)
Find proteins for P01892 (Homo sapiens)
Go to Gene View: HLA-A
Go to UniProtKB:  P01892
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Beta-2-microglobulin
B, E
100Homo sapiensMutation(s): 0 
Gene Names: B2M
Find proteins for P61769 (Homo sapiens)
Go to Gene View: B2M
Go to UniProtKB:  P61769
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
Trans-activating transcriptional regulatory peptide
C, F
9Human T-cell leukemia virus 1Mutation(s): 0 
Gene Names: tax
Find proteins for P14079 (Human T-cell leukemia virus 1)
Go to UniProtKB:  P14079
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
GOL
Query on GOL

Download SDF File 
Download CCD File 
A, B, D, E, F
GLYCEROL
GLYCERIN; PROPANE-1,2,3-TRIOL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.05 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.171 
  • Space Group: P 1
Unit Cell:
Length (Å)Angle (°)
a = 50.320α = 82.13
b = 62.532β = 76.57
c = 74.801γ = 78.06
Software Package:
Software NamePurpose
HKL-2000data scaling
HKL-2000data reduction
REFMACrefinement
MOLREPphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-10-18
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Advisory, Version format compliance
  • Version 1.3: 2012-12-12
    Type: Other
  • Version 1.4: 2013-03-13
    Type: Other