The outline structure of the T-cell alpha beta receptor.
From an analysis of the immunoglobulins of known structure we derive a list of 40 sites crucial for the conserved structure of the variable domains. We show that, with marginal exceptions, the sequences of the T-cell alpha beta receptors contain, at sites homologous to these 40, the same or very similar residues. Thus the V alpha-V beta dimer has a framework structure very close to that of the immunoglobulins. Further comparisons show that parts of the surface of the V alpha-V beta framework are hypervariable. They also show that the loops that form the antigen-binding site are similar in size to those commonly found in the immunoglobulins but have different conformations. Only limited sequence variations occur in the first loop of the antigen-binding site in both V alpha and V beta. This, and their geometrical arrangement, suggest that they mainly interact with the MHC proteins.
Chothia
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MRC Laboratory of Molecular Biology, Cambridge, UK.
Boswell
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Lesk
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D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000648:ultrastructure; D051379:Mice; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011948:Receptors, Antigen, T-Cell / Q000648:ultrastructure*
D007135:Immunoglobulin Variable Region; D011948:Receptors, Antigen, T-Cell