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Title
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The three-dimensional structure of HLA-B27 at 2.1 A resolution suggests a general mechanism for tight peptide binding to MHC.
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Authors
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D.R.Madden,
J.C.Gorga,
J.L.Strominger,
D.C.Wiley.
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Ref.
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Cell, 1992,
70,
1035-1048.
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PubMed id
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Abstract
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Cell surface complexes of class I MHC molecules and bound peptide antigens serve
as specific recognition elements controlling the cytotoxic immune response. The
2.1 A structure of the human class I MHC molecule HLA-B27 provides a detailed
composite image of a co-crystallized collection of HLA-B27-bound peptides,
indicating that they share a common main-chain structure and length. It also
permits direct visualization of the conservation of arginine as an
"anchor" side chain at the second peptide position, which is bound in
a potentially HLA-B27-specific pocket and may therefore have a role in the
association of HLA-B27 with several diseases. Tight peptide binding to class I
MHC molecules appears to result from the extensive contacts found at the ends of
the cleft between peptide main-chain atoms and conserved MHC side chains, which
also involve the peptide in stabilizing the three-dimensional fold of HLA-B27.
The concentration of binding interactions at the peptide termini permits
extensive sequence (and probably some length) variability in the center of the
peptide, where it is exposed for T cell recognition.
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