Abstract
Purified major histocompatibility complex (MHC) class I molecules have been studied at high resolution by X-ray crystallography; the structure is a complex of a single heavy chain, a beta 2-microglobulin light chain and a tightly bound peptide moiety. We show here that complete MHC class I molecules are post-translationally assembled into tetramers (made up of four heavy chains and four beta 2-microglobulin units) and that this tetrameric species is expressed on the cell surface. The multivalent tetrameric structure of class I molecules can be reconciled with models of T-cell activation that invoke antigen-receptor crosslinking, as opposed to models that depend on an allosteric change.
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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Animals
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Antibodies
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Autoradiography
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Cell Line
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Cell Membrane / immunology
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Cross-Linking Reagents
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Electrophoresis, Gel, Two-Dimensional
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Electrophoresis, Polyacrylamide Gel
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Histocompatibility Antigens Class I / biosynthesis
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Histocompatibility Antigens Class I / chemistry*
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Histocompatibility Antigens Class I / isolation & purification
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Lymphocytes / immunology
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Macromolecular Substances
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Methionine / metabolism
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Mice
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Mice, Inbred BALB C
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Sulfur Radioisotopes
Substances
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Antibodies
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Cross-Linking Reagents
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Histocompatibility Antigens Class I
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Macromolecular Substances
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Sulfur Radioisotopes
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Methionine