The three-dimensional structure of a T-cell antigen receptor V alpha V beta heterodimer reveals a novel arrangement of the V beta domain

摘要: The crystal structure of a mouse T-cell antigen receptor (TCR) Fv fragment complexed to the Fab specific anti-clonotypic antibody has been determined 2.6 A resolution. polypeptide backbone TCR V alpha domain is very similar those other crystallographically alphas, whereas beta so far unique among domains in that it displays switch c" strand from inner outer beta-sheet. chain variable region this antigen-binding site characterized by rather elongated third complementarity-determining (CDR3beta) packs tightly against CDR3 loop chain, without leaving any intervening hydrophobic pocket. Thus, conformation CDR loops with highest potential diversity distinguishes for which crystallographic data are available. On basis all these results, we infer significant conformational change CDR3beta found our required binding its cognate peptide-MHC ligand.