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The crystal structure of the high affinity TCR A6The crystal structure of the high affinity TCR A6
Structural highlights
Publication Abstract from PubMedNatural T cell receptors (TCRs) generally bind to their cognate pMHC molecules with weak affinity and fast kinetics, limiting their use as therapeutic agents. Using phage display, we have engineered a high affinity version of the A6 wild-type TCR (A6wt), specific for the human leukocyte antigen (HLA-A( *)0201) complexed with human T cell lymphotropic virus type 111-19 peptide (A2-Tax). Mutations in just 4 residues in the CDR3beta loop region of the A6wt TCR were selected that improved binding to A2-Tax by nearly 1000-fold. Biophysical measurements of this mutant TCR (A6c134) demonstrated that the enhanced binding was derived through favorable enthalpy and a slower off-rate. The structure of the free A6c134 TCR and the A6c134/A2-Tax complex revealed a native binding mode, similar to the A6wt/A2-Tax complex. However, concordant with the more favorable binding enthalpy, the A6c134 TCR made increased contacts with the Tax peptide compared with the A6wt/A2-Tax complex, demonstrating a peptide-focused mechanism for the enhanced affinity that directly involved the mutated residues in the A6c134 TCR CDR3beta loop. This peptide-focused enhanced TCR binding may represent an important approach for developing antigen specific high affinity TCR reagents for use in T cell based therapies. Increased Peptide Contacts Govern High Affinity Binding of a Modified TCR Whilst Maintaining a Native pMHC Docking Mode.,Cole DK, Sami M, Scott DR, Rizkallah PJ, Borbulevych OY, Todorov PT, Moysey RK, Jakobsen BK, Boulter JM, Baker BM, Yi Li Front Immunol. 2013 Jun 26;4:168. doi: 10.3389/fimmu.2013.00168. Print 2013. PMID:23805144[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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