Abstract
The rat MHC class Ia molecule RT1-Aa has the unusual capacity to bind long peptides ending in arginine, such as MTF-E, a thirteen-residue, maternally transmitted minor histocompatibility antigen. The antigenic structure of MTF-E was unpredictable due to its extraordinary length and two arginines that could serve as potential anchor residues. The crystal structure of RT1-Aa-MTF-E at 2.55 A shows that both peptide termini are anchored, as in other class I molecules, but the central residues in two independent pMHC complexes adopt completely different bulged conformations based on local environment. The MTF-E epitope is fully exposed within the putative T cell receptor (TCR) footprint. The flexibility demonstrated by the MTF-E structures illustrates how different TCRs may be raised against chemically identical, but structurally dissimilar, pMHC complexes.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adenosine Triphosphatases / chemistry*
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Adenosine Triphosphatases / immunology
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Animals
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Crystallography, X-Ray
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Epitopes, T-Lymphocyte / chemistry*
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Epitopes, T-Lymphocyte / immunology
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Histocompatibility Antigens / chemistry*
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Histocompatibility Antigens / immunology
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Histocompatibility Antigens Class I / chemistry*
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Histocompatibility Antigens Class I / immunology
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Minor Histocompatibility Antigens / chemistry*
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Minor Histocompatibility Antigens / immunology
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Mitochondrial Proton-Translocating ATPases
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Models, Molecular
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Peptides / chemistry*
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Peptides / immunology
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Protein Structure, Secondary
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Rats
Substances
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Epitopes, T-Lymphocyte
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Histocompatibility Antigens
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Histocompatibility Antigens Class I
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Minor Histocompatibility Antigens
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Peptides
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histocompatibility antigens RT, rat
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Adenosine Triphosphatases
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Mitochondrial Proton-Translocating ATPases