中文摘要：

赖氨酸是蛋白质的翻译后修饰位点以及多种酶活性中心关键残基,与蛋白质的结构与功能密切相关。应用遗传密码扩充技术,由来自于M.barkeri的吡咯赖氨酰tRNA合成酶（PylRS）和吡咯赖氨酰tRNA（tRNA-Pyl）构成非天然氨基酸定点引入系统,可以实现蛋白质中赖氨酸残基的定点修饰,在蛋白质中定点引入乙酰基等翻译后修饰基团、光反应基团、正交反应基团和光谱活性基团等。目前该系统已在大肠杆菌、酵母菌、哺乳动物细胞中及线虫体内成功地将10种赖氨酸衍生物编码入蛋白质中,为研究蛋白质翻译后修饰、定点标记和定点修饰、蛋白质相互作用提供了有力的工具。综述了应用该系统在蛋白质中定点引入赖氨酸衍生物的应用研究进展,并分析了该系统与目前最常用的系统相比的优势所在。

英文摘要：

Lysine residues are the target of key post-translational modifications, including acetylation, methylation and ubiquitina- tion, and the key residues in many important enzyme active sites as well. However, neither the impact of most post-translational modi- fications on protein function nor the modifying enzymes have been identified. Genetic code expansion offers the possibility to directly incorporate unnatural amino acids into proteins. The UAAs, which can be used as spectroscopic probes, to photo-cage proteins, for labelling in bioorthogonal reactions or to introduce post-translational modifications and much more,introduce exciting new features into proteins. The engagement of a special codon, usually a rarely-used stop codon or a quadruplet codon, and a unique aminoacyl-tRNA synthetase/tRNA pair that can be used to accommodate a broad range of UAAs while maintaining strict orthogonality in a variety of prokaryotic and eukaryotic expression systems has proven an invaluable combination. Methanosarcinaceae Pyrrolysyl-tRNA syntheta- ses and their cognate suppressor tRNAs are used to genetically encode lysine analogs into proteins in E. coil,yeast, mammalian cells and even multicellular organisms. Tens of different lysine derivatives and analogs with different functional groups, including acetyl, methyl, ubiquitin, azido, fluoro, nitro and photo-crosslinkers, have been encoded to date, which offers a vast potential for applications in protein chemistry,biochemistry and cell biology. The present study on the PylRS/tRNAeyl system has provided powerful tools for studies on protein-protein and protein-DNA interactions, post-translational modification, site-specific labeling, and cell-cell interac- tions and signalling. The application of site-specific incorporation of lysine analogs into proteins has been reviewed. The advantages of this system, compared with other cognate pairs, have been also discussed.