Madura F, Rizkallah PJ, Miles KM, Holland CJ, Bulek AM, Fuller A, Schauenburg AJA, Miles JJ, Liddy N, Sami M, Li Y, Hossain M, Baker BM, Jakobsen BK, Sewell AK, Cole DK. T-cell receptor specificity maintained by altered thermodynamics.
J Biol Chem 2013;
288:18766-75. [PMID:
23698002 PMCID:
PMC3696650 DOI:
10.1074/jbc.m113.464560]
[Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The T-cell receptor (TCR) recognizes peptides bound to major histocompatibility molecules (MHC) and allows T-cells to interrogate the cellular proteome for internal anomalies from the cell surface. The TCR contacts both MHC and peptide in an interaction characterized by weak affinity (KD = 100 nM to 270 μM). We used phage-display to produce a melanoma-specific TCR (α24β17) with a 30,000-fold enhanced binding affinity (KD = 0.6 nM) to aid our exploration of the molecular mechanisms utilized to maintain peptide specificity. Remarkably, although the enhanced affinity was mediated primarily through new TCR-MHC contacts, α24β17 remained acutely sensitive to modifications at every position along the peptide backbone, mimicking the specificity of the wild type TCR. Thermodynamic analyses revealed an important role for solvation in directing peptide specificity. These findings advance our understanding of the molecular mechanisms that can govern the exquisite peptide specificity characteristic of TCR recognition.
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