非天然氨基酸在蛋白质动态特性核磁共振研究中的应用

核磁共振（NMR）是蛋白质结构解析的主要方法之一.除可获得蛋白质的高分辨结构外，NMR还可用于观测最接近生理条件的蛋白质动态构象，获得蛋白质行使生物学功能的详细机制.非天然氨基酸定点标记方法可显著减少大分子量蛋白质的信号数目，降低数据采集和分析难度，已广泛运用于蛋白质结构和功能研究.本文介绍了常用的在蛋白质中引入非天然氨基酸的实验方法，包括蛋白质化学合成法、蛋白质化学修饰法、氟代芳香族氨基酸插入和基因密码子编辑的位点特异性插入等方法，并介绍了部分应用非天然氨基酸结合NMR研究大分子量蛋白的成功案例.此外，此篇综述讨论了目前非天然氨基酸标记在蛋白质研究中的局限性及发展方向.

NMR Studies of Large Protein Dynamics Using Unnatural Amino Acids

Nuclear magnetic resonance (NMR) is a major method used to study protein structure at atomic resolution. Besides presenting the high-resolution structure, NMR facilitates studies on protein dynamics near physiological conditions that are intimately related to the biological mechanism of the proteins. Unnatural amino acids (UAA) labeling could significantly reduce the complexity of protein NMR spectra. In this review, we briefly summarize the widely used UAA labeling strategies for proteins, including chemical peptide synthesis, residue-specific peptide modification, ¹⁹F labeled aromatic amino acids incorporation and genetic code expansion based UAA incorporation. The recent applicants of UAA in characterizing protein structure and dynamics, the limitations and prospects of UAA are also highlighted.