{"display":true,"structure":{"allele":{"alpha":{"identifier":"ipd-imgt:HLA35266","locus":"hla-a","match_type":"histo:exact","name":"HLA-A*02:01","slug":"hla_a_02_01","species_stem":"hla"},"beta":{}},"assemblies":{"1":{"assembly_name":"7llj_1","chains":["K","L","C","D"],"downloaded_at":"2022-11-09T14:38:55.769120"},"2":{"assembly_name":"7llj_2","chains":["A","B","E","F"],"downloaded_at":"2022-11-09T14:38:56.506351"}},"assembly_count":null,"assigned_chains":{"beta2m":{"chains":["D","H"],"match_type":"histo:override","sequence":"MIQRTPKIQVYSRHPAENGKSNFLNCYVSGFHPSDIEVDLLKNGERIEKVEHSDLSFSKDWSFYLLYYTEFTPTEKDEYACRVNHVTLSQPKIVKWDRDM"},"mr1":{"chains":["C","G"],"match_type":"histo:override","sequence":"MRTHSLRYFRLGVSDPIHGVPEFISVGYVDSHPITTYDSVTRQKEPRAPWMAENLAPDHWERYTQLLRGWQQMFKVELKRLQRHYNHSGSHTYQRMIGCELLEDGSTTGFLQYAYDGQDFLIFNKDTLSWLAVDNVAHTIKQAWEANQHELLYQKNWLEEECIAWLKRFLEYGKDTLQRTEPPLVRVNRKETFPGVTALFCKAHGFYPPEIYMTWMKNGEEIVQEIDYGDILPSGDGTYQAWASIELDPQSSNLYSCHVEHSGVHMVLQVP"},"note":"not yet in STCRdab","tcr_delta":{"chains":["L","B"],"match_type":"histo:override","sequence":"SDKVTQSSPDQTVASGSEVVLLCTYDTVYSNPDLFWYRIRPDYSFQFVFYGDNSRSEGADFTQGRFSVKHILTQKAFHLVISPVRTEDSATYYCATRLWLGDPHTDKLIFGKGTRVTVEPNIQNPDPAVYQLRDSKSSDKSVCLFTDFDSQTNVSQSKDSDVYITDKCVLDMRSMDFKSNSAVAWSNKSDFACANAFNNSIIPEDTFFPSPESS"},"tcr_gamma":{"chains":["K","A"],"match_type":"histo:override","sequence":"TGSSNLEGRTKSVTRPTGSSAVITCDLPVENAVYTHWYLHQEGKAPQRLLYYDSYNSRVVLESGISREKYHTYASTGKSLKFILENLIERDSGVYYCATWDYKKLFGSGTTLVVTEDLKNVFPPEVAVFEPSEAEISHTQKATLVCLATGFYPDHVELSWWVNGKEVHSGVCTDPQPLKEQPALNDSRYALSSRLRVSATFWQNPRNHFRCQVQFYGLSENDEWTQDRAKPVTQIVSAEAWGRAD"}},"chronology":{"deposition_date":"2021-02-04","deposition_year":2021,"release_date":"2021-11-17","release_year":2021,"revision_date":"2021-12-08","revision_year":2021},"class":"class_i","classical":false,"complex_type":"mr1_with_gamma_delta_tcr","components":["mr1","beta2m","tcr_delta","tcr_gamma"],"experimental_method":"X-ray diffraction","facets":{},"ligands":[],"locus":"hla-a","manually_edited":{},"missing_residues":[],"page_title":"7LLJ | Non-classical MHC Class I molecule MR1 with Gamma/Delta T cell receptor","pdb_code":"7llj","pdb_title":"Inhibitory immune receptor protein complex","peptide":{"actual_sequence":null,"epitope_info":{},"features":[],"full_sequence":null,"gap_info":{},"gapped_sequence":null,"length":{"numeric":null,"text":null},"unnatural_amino_acids":[]},"publication":{"abstract":"Unlike conventional \u03b1\u03b2 T cells, \u03b3\u03b4 T cells typically recognize nonpeptide ligands independently of major histocompatibility complex (MHC) restriction. Accordingly, the \u03b3\u03b4 T cell receptor (TCR) can potentially recognize a wide array of ligands; however, few ligands have been described to date. While there is a growing appreciation of the molecular bases underpinning variable (V)\u03b41<sup>+</sup> and V\u03b42<sup>+</sup> \u03b3\u03b4 TCR-mediated ligand recognition, the mode of V\u03b43<sup>+</sup> TCR ligand engagement is unknown. MHC class I-related protein, MR1, presents vitamin B metabolites to \u03b1\u03b2 T cells known as mucosal-associated invariant T cells, diverse MR1-restricted T cells, and a subset of human \u03b3\u03b4 T cells. Here, we identify V\u03b41/2<sup>-</sup> \u03b3\u03b4 T cells in the blood and duodenal biopsy specimens of children that showed metabolite-independent binding of MR1 tetramers. Characterization of one V\u03b43V\u03b38 TCR clone showed MR1 reactivity was independent of the presented antigen. Determination of two V\u03b43V\u03b38 TCR-MR1-antigen complex structures revealed a recognition mechanism by the V\u03b43 TCR chain that mediated specific contacts to the side of the MR1 antigen-binding groove, representing a previously uncharacterized MR1 docking topology. The binding of the V\u03b43<sup>+</sup> TCR to MR1 did not involve contacts with the presented antigen, providing a basis for understanding its inherent MR1 autoreactivity. We provide molecular insight into antigen-independent recognition of MR1 by a V\u03b43<sup>+</sup> \u03b3\u03b4 TCR that strengthens an emerging paradigm of antibody-like ligand engagement by \u03b3\u03b4 TCRs.","bibjson":{"author":[{"initials":"MT","lastname":"Rice","name":"Rice MT"},{"initials":"A","lastname":"von Borstel","name":"von Borstel A"},{"initials":"P","lastname":"Chevour","name":"Chevour P"},{"initials":"W","lastname":"Awad","name":"Awad W"},{"initials":"LJ","lastname":"Howson","name":"Howson LJ"},{"initials":"DR","lastname":"Littler","name":"Littler DR"},{"initials":"NA","lastname":"Gherardin","name":"Gherardin NA"},{"initials":"J","lastname":"Le Nours","name":"Le Nours J"},{"initials":"EM","lastname":"Giles","name":"Giles EM"},{"initials":"R","lastname":"Berry","name":"Berry R"},{"initials":"DI","lastname":"Godfrey","name":"Godfrey DI"},{"initials":"MS","lastname":"Davey","name":"Davey MS"},{"initials":"J","lastname":"Rossjohn","name":"Rossjohn J"},{"initials":"BS","lastname":"Gully","name":"Gully BS"}],"identifier":[{"id":"10.1073/pnas.2110288118","type":"doi"},{"id":"34845016","type":"pubmed"}],"issue":["49"],"journal":{"iso_abbreviation":"Proc Natl Acad Sci U S A","name":""},"pages":[null],"title":"Recognition of the antigen-presenting molecule MR1 by a V\ufffd\ufffd3<sub>+</sub> \ufffd\ufffd\ufffd\ufffd T cell receptor.","type":"article","url":"https://pnas.org/doi/full/10.1073/pnas.2110288118","volume":["118"],"year":[2021]},"in_pmc":"N","in_pmce":"Y","open_access":"N"},"resolution":"3.15","same_as":{"pdbe":{"url":"https://www.ebi.ac.uk/pdbe/entry/pdb/7llj"},"rcsb":{"url":"https://www.rcsb.org/structure/7llj"}},"species":{"common_name":"Human","match_type":"histo:assign_species","scientific_name":"Homo sapiens","slug":"homo_sapiens"},"tcr":null,"title":"Non-classical MHC Class I molecule MR1 with Gamma/Delta T cell receptor at 3.15&#8491; resolution","unique_chain_count":4}}