An alphabeta T cell receptor structure at 2.5 A and its orientation in the TCR-MHC complex.

摘要: The central event in the cellular immune response to invading microorganisms is specific recognition of foreign peptides bound major histocompatibility complex (MHC) molecules by αβ T cell receptor (TCR). x-ray structure complete extracellular fragment a glycosylated TCR was determined at 2.5 angstroms, and its orientation class I MHC-peptide (pMHC) elucidated from crystals TCR-pMHC complex. resembles an antibody variable Vα Vβ domains but deviates constant Cα domain interdomain pairing with Cβ. Four seven possible asparagine-linked glycosylation sites have ordered carbohydrate moieties, one which lies Cα-Cβ interface. combining site relatively flat except for deep hydrophobic cavity between hypervariable CDR3s (complementarity-determining regions) α β chains. 2C covers MHC H-2K b binding groove so that CDRs 1 2 are positioned over amino-terminal region dEV8 peptide, chain carboxyl-terminal straddle peptide helices around position peptide.