[An alternative model of structural organization of the ternary complex antigen-protein MHC II-TCR].

An alternative model of organization of the structure of ternary complex "antigen-molecule" of the main complex of histocompatible class II (MHC II)--antigenic receptor of T-cells (TCR) is suggested. In contrast to the already developed ones the new model foresees TCR interaction with only one (beta)-chain of the molecule MHC (II), with its surface site having the structure of alpha-spiral. The second (alpha)-chain of the molecule MHC II performs only antigen-binding and supporting function. According to the structure of the code of amino acids interaction a comparative analysis of the roots (bases of the second nucleotides) of amino acid codons of fragments of alpha-, beta-, and gamma-invariant chains of MHC II, as well as some antigens and immunoregulators. An expressed similarity of the structures of spiral fragment of beta- and gamma-chains of MHC II both between themselves and with certain antigens and natural immunoregulators.