Department of Microbiology, 484 West 12th Avenue, The Ohio State University, Columbus, OH 43210, United States.
Curr Opin Microbiol. 2011 Jun;14(3):342-9. doi: 10.1016/j.mib.2011.04.001. Epub 2011 May 5.
In Methanosarcina spp., amber codons in methylamine methyltransferase genes are translated as the 22nd amino acid, pyrrolysine. The responsible pyl genes plus amber-codon containing methyltransferase genes have been identified in four archaeal and five bacterial genera, including one human pathogen. In Escherichia coli, the recombinant pylBCD gene products biosynthesize pyrrolysine from two molecules of lysine and the pylTS gene products direct pyrrolysine incorporation into protein. In the proposed biosynthetic pathway, PylB forms methylornithine from lysine, which is joined to another lysine by PylC, and oxidized to pyrrolysine by PylD. Structures of the catalytic domain of pyrrolysyl-tRNA synthetase (archaeal PylS or bacterial PylSc) revealed binding sites for tRNAPyl and pyrrolysine. PylS and tRNAPyl are now being exploited as an orthogonal pair in recombinant systems for introduction of useful modified amino acids into proteins.
在 Methanosarcina spp. 中，亚精胺甲基转移酶基因中的琥珀密码子被翻译为第 22 种氨基酸，吡咯赖氨酸。负责的 pyl 基因加上含有琥珀密码子的甲基转移酶基因已在四个古菌属和五个细菌属中被鉴定出来，其中包括一个人类病原体。在大肠杆菌中，重组的 pylBCD 基因产物从两个赖氨酸分子合成吡咯赖氨酸，而 pylTS 基因产物则指导吡咯赖氨酸掺入蛋白质。在拟议的生物合成途径中，PylB 从赖氨酸形成甲基鸟氨酸，PylC 将其与另一个赖氨酸连接，然后 PylD 将其氧化为吡咯赖氨酸。吡咯赖氨酸-tRNA 合成酶（古菌 PylS 或细菌 PylSc）催化结构域的结构揭示了与 tRNAPyl 和吡咯赖氨酸的结合位点。PylS 和 tRNAPyl 现在被用作重组系统中的正交对，用于将有用的修饰氨基酸引入蛋白质。
