1T1W

Structural basis for degenerate recognition of HIV peptide variants by cytotoxic lymphocyte, variant SL9-3F6I8V

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.182 

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This is version 1.2 of the entry. See complete history. 


Literature

Structural Basis for Degenerate Recognition of Natural HIV Peptide Variants by Cytotoxic Lymphocytes.

Martinez-Hackert, E., Anikeeva, N., Kalams, S.A., Walker, B.D., Hendrickson, W.A., Sykulev, Y.

(2006) J Biol Chem 281: 20205-20212

  • DOI: 10.1074/jbc.M601934200
  • Primary Citation of Related Structures:  
    1T22, 1T21, 1T20, 1T1Z, 1T1Y, 1T1X, 1T1W, 1S8D

  • PubMed Abstract: 

    • It is well established that even small changes in amino acid side chains of antigenic peptide bound to major histocompatibility complex (MHC) protein may completely abrogate recognition of the peptide-MHC (pMHC) complex by the T cell receptor (TCR). ...

    It is well established that even small changes in amino acid side chains of antigenic peptide bound to major histocompatibility complex (MHC) protein may completely abrogate recognition of the peptide-MHC (pMHC) complex by the T cell receptor (TCR). Often, however, several nonconservative substitutions in the peptide antigen are accommodated and do not impair its recognition by TCR. For example, a preponderance of natural sequence variants of the human immunodeficiency virus p17 Gag-derived peptide SLYNTVATL (SL9) are recognized by cytotoxic T lymphocytes, which implies that interactions with SL9 variants are degenerate both with respect to the class I MHC molecule and with respect to TCR. Here we study the molecular basis for this degenerate recognition of SL9 variants. We show that several SL9 variants bind comparably well to soluble HLA-A2 and to a particular soluble TCR and that these variants are active in the cognate cytotoxicity assay. Natural SL9 variation is restricted by its context in the HIV p17 matrix protein. High resolution crystal structures of seven selected SL9 variants bound to HLA-A2 all have remarkably similar peptide conformations and side-chain dispositions outside sites of substitution. This preservation of the peptide conformation despite epitope variations suggests a mechanism for the observed degeneracy in pMHC recognition by TCR and may contribute to the persistence of SL9-mediated immune responses in chronically infected individuals.

    Organizational Affiliation: 

    Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
HLA class I histocompatibility antigen, A-2 alpha chainA275Homo sapiensMutation(s): 0 
Gene Names: HLA-A, HLAA
Find proteins for P04439 (Homo sapiens)
Explore P04439 
Go to UniProtKB:  P04439
NIH Common Fund Data Resources
PHAROS  P04439
GTEx  ENSG00000206503
Protein Feature View
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  • Reference Sequence
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(by identity cutoff)  |  Structure
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Beta-2-microglobulinB99Homo sapiensMutation(s): 0 
Gene Names: B2M, CDABP0092, HDCMA22P
Find proteins for P61769 (Homo sapiens)
Explore P61769 
Go to UniProtKB:  P61769
NIH Common Fund Data Resources
PHAROS  P61769
GTEx  ENSG00000166710
Protein Feature View
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  • Reference Sequence
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Entity ID: 3
MoleculeChainsSequence LengthOrganismDetailsImage
GAG PEPTIDEC9N/AMutation(s): 0 
Find proteins for O11822 (Human immunodeficiency virus 1)
Explore O11822 
Go to UniProtKB:  O11822
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.182 
  • R-Value Observed: 0.182 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 55.81α = 90
b = 80.03β = 116.21
c = 57.68γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
CNSrefinement
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2005-09-06
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance