Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, United Kingdom.
J Biol Chem. 2013 Jun 28;288(26):18766-75. doi: 10.1074/jbc.M113.464560. Epub 2013 May 22.
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.
T 细胞受体 (TCR) 识别与主要组织相容性分子 (MHC) 结合的肽，并允许 T 细胞从细胞表面检测细胞蛋白质组中的内部异常。TCR 与 MHC 和肽相互作用，其亲和力较弱（KD = 100 nM 至 270 μM）。我们使用噬菌体展示技术产生了一种具有 30,000 倍增强结合亲和力（KD = 0.6 nM）的黑色素瘤特异性 TCR（α24β17），以帮助我们探索用于维持肽特异性的分子机制。值得注意的是，尽管增强的亲和力主要是通过新的 TCR-MHC 接触介导的，但 α24β17 仍然对肽骨架上每个位置的修饰非常敏感，模拟了野生型 TCR 的特异性。热力学分析揭示了溶剂化在指导肽特异性方面的重要作用。这些发现提高了我们对分子机制的理解，这些机制可以控制 TCR 识别的肽特异性的精细特征。
