| Abstract: | This paper attempts to describe a great variety of allelic forms of mammalian major histocompatibility gene complex (MHC) Class I molecules as a single "formula" that contains information on motifs in their primary structure. The positions of amino acid residues that are invariant even in highly evolutionarily different species have been found in the structure of MHC Class I molecular domains that are recognizable by T-cell receptors (TCR). The spatial arrangement of invariant residues in the tertiary structure of MHC molecules is indicative of their structure-forming function: they are generally located at the sites of contact of alpha-helices and beta-sheets. A study of homology between the structures of MHC Classes I and II molecules has identified a fragment located in the "kink"-region of both MHC Class I and beta-chains of MHC class II molecules, at which the spectra of possible amino acid substitutions significantly coincide. Since this region can act as an "anchor" for interaction with TCR, the authors have synthesized dendrimers with the direct and inverse sequences of AA158-175 of an H-2Ld molecule, whose biological activity has been investigated in the fetal thymic organ cultures isolated from 14-day embryos of B10.D2 (KdIdDdLd) mice. The findings suggest that synthesized peptides can affect the development and shaping of T-cell repertoire. |
