title: T-cell receptor specificity maintained by altered thermodynamics.
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.
authors.affiliation: Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, United Kingdom.
authors.forename: Florian
authors.initials: F
authors.lastname: Madura
authors.forename: Pierre J
authors.initials: PJ
authors.lastname: Rizkallah
authors.forename: Kim M
authors.initials: KM
authors.lastname: Miles
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Holland
authors.forename: Anna M
authors.initials: AM
authors.lastname: Bulek
authors.forename: Anna
authors.initials: A
authors.lastname: Fuller
authors.forename: Andrea J A
authors.initials: AJ
authors.lastname: Schauenburg
authors.forename: John J
authors.initials: JJ
authors.lastname: Miles
authors.forename: Nathaniel
authors.initials: N
authors.lastname: Liddy
authors.forename: Malkit
authors.initials: M
authors.lastname: Sami
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.forename: Moushumi
authors.initials: M
authors.lastname: Hossain
authors.forename: Brian M
authors.initials: BM
authors.lastname: Baker
authors.forename: Bent K
authors.initials: BK
authors.lastname: Jakobsen
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Sewell
authors.forename: David K
authors.initials: DK
authors.lastname: Cole
mesh_terms: D000409:Alanine; D019921:Biotinylation; D018360:Crystallography, X-Ray; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D006860:Hydrogen Bonding; D008285:Major Histocompatibility Complex; D008545:Melanoma / Q000378:metabolism*; D008968:Molecular Conformation; D009154:Mutation; D019151:Peptide Library; D010455:Peptides / Q000378:metabolism; D011485:Protein Binding; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D012997:Solvents; D020349:Surface Plasmon Resonance; D037182:T-Cell Antigen Receptor Specificity; D013816:Thermodynamics; D014867:Water
chemical_list: D019151:Peptide Library; D010455:Peptides; D011948:Receptors, Antigen, T-Cell; D012997:Solvents; D014867:Water; D000409:Alanine
keywords: Crystal Structure; High Affinity T Cell Receptor (TCR); Melanoma; Peptide-major Histocompatibility Complex (pMHC); Surface Plasmon Resonance (SPR); T-cell; T-cell Receptor