A T cell receptor flattens a bulged antigenic peptide presented by a major histocompatibility complex class I molecule

作者:Tynan Fleur E; Reid Hugh H; Kjer Nielsen Lars; Miles John J; Wilce Matthew C J; Kostenko Lyudmila; Borg Natalie A; Williamson Nicholas A; Beddoe Travis; Purcell Anthony W; Burrows Scott R; McCluskey James*; Rossjohn Jamie
来源:Nature Immunology, 2007, 8(3): 268-276.
DOI:10.1038/ni1432

摘要

Plasticity of the T cell receptor (TCR) is a hallmark of major histocompatibility complex (MHC)-restricted T cell recognition. However, it is unclear whether interactions of TCR and peptide-MHC class I ( pMHCI) always conform to this paradigm. Here we describe the structure of a TCR, ELS4, in its non-ligand-bound form and in complex with a prominent 'bulged' Epstein-Barr virus peptide bound to HLA-B*3501. This complex was atypical of previously characterized TCR-pMHCI interactions in that a rigid face of the TCR crumpled the bulged antigenic determinant. This peptide 'bulldozing' created a more featureless pMHCI determinant, allowing the TCR to maximize MHC class I contacts essential for MHC class I restriction of TCR recognition. Our findings represent a mechanism of antigen recognition whereby the plasticity of the T cell response is dictated mainly by adjustments in the MHC-bound peptide.