title: Possible conformation of major histocompatibility antigens: implication of amino acid sequence data.
abstract: Possible conformation of major histocompatibility antigens was proposed on the basis of homology between domains of major histocompatibility antigen polypeptide chains and domains of immunoglobulins, characterized by a beta-pleated structure. In the hypothetical three-dimensional structure, domains alpha 3 and alpha 2 interact along the chain similarly to the CH2 and CH3 domains of IgG. beta 2-Microglobulin together with domain alpha 2 forms a structure analogous to the CH3--CH3 or CH1--CL dimers in IgG. Domains alpha 2 ans alpha 1 interact in such a manner that the beta-pleated sheet of domain alpha 2 is directly joined to the beta-pleated sheet of domain alpha 1. Hypervariable regions in domains alpha 1 and alpha 2, which most likely take part in the formation of the alloantigen determinants, represent the loops joining the regions of the beta-pleated structure. Domains alpha 1 and alpha 2 may be packed in such a way that their hypervariable regions would become adjacent and would be located on their surface turned aside from the surface of the cell membrane.
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D006680:HLA Antigens / Q000032:analysis*; D006801:Humans; D007141:Immunoglobulin Fc Fragments / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D066298:In Vitro Techniques; D011487:Protein Conformation
chemical_list: D006680:HLA Antigens; D007141:Immunoglobulin Fc Fragments; D007074:Immunoglobulin G