title: A T cell receptor flattens a bulged antigenic peptide presented by a major histocompatibility complex class I molecule.
abstract: 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.
authors.affiliation: Protein Crystallography Unit, Department of Biochemistry and Molecular Biology, School of Biomedical Sciences, Monash University, Clayton, Victoria 3800, Australia.
authors.forename: Fleur E
authors.initials: FE
authors.lastname: Tynan
authors.forename: Hugh H
authors.initials: HH
authors.lastname: Reid
authors.forename: Lars
authors.initials: L
authors.lastname: Kjer-Nielsen
authors.forename: John J
authors.initials: JJ
authors.lastname: Miles
authors.forename: Matthew C J
authors.initials: MC
authors.lastname: Wilce
authors.forename: Lyudmila
authors.initials: L
authors.lastname: Kostenko
authors.forename: Natalie A
authors.initials: NA
authors.lastname: Borg
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Williamson
authors.forename: Travis
authors.initials: T
authors.lastname: Beddoe
authors.forename: Anthony W
authors.initials: AW
authors.lastname: Purcell
authors.forename: Scott R
authors.initials: SR
authors.lastname: Burrows
authors.forename: James
authors.initials: J
authors.lastname: McCluskey
authors.forename: Jamie
authors.initials: J
authors.lastname: Rossjohn
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000276:immunology*; D000956:Antigens, Viral / Q000737:chemistry* / Q000276:immunology; D018984:Epitopes, T-Lymphocyte / Q000737:chemistry* / Q000276:immunology; D005434:Flow Cytometry; D015395:Histocompatibility Antigens Class I / Q000737:chemistry* / Q000276:immunology; D006801:Humans; D020836:Protein Structure, Quaternary; D011948:Receptors, Antigen, T-Cell / Q000737:chemistry* / Q000276:immunology
chemical_list: D000956:Antigens, Viral; D018984:Epitopes, T-Lymphocyte; D015395:Histocompatibility Antigens Class I; D011948:Receptors, Antigen, T-Cell