T-cell receptor specificity maintained by altered thermodynamics.

TitleT-cell receptor specificity maintained by altered thermodynamics.
Publication TypeJournal Article
Year of Publication2013
AuthorsMadura 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
JournalThe Journal of biological chemistry
Volume288
Issue26
Pagination18766-75
Date Published2013 Jun 28
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.

DOI10.1128/JCM.00859-13
Alternate JournalJ. Biol. Chem.