Expanding the Genetic Code with Phosphoserine

合成含有遗传密码外氨基酸的蛋白质最近重新成为一个非常感兴趣的话题，并在智力和技术上提出了巨大的挑战。重编程遗传密码需要两个关键事件：(i)创建一个新的高效的“正交”氨基酰基tRNA合成酶：tRNA对能够单独产生非规范的氨基酰基tRNA。（ii）通过重新编码特定的mRNA密码子来指定该氨基酸插入蛋白质的位置的能力。基于最近发现的甲烷原氨基酰基合成酶样蛋白、o -磷酸丝氨酸tRNA合成酶及其同源蛋白tRNACys的天然存在性，将开展基于信使RNA中无义密码子UAG将磷酸丝氨酸插入多肽预定位置的原核和真核系统的研究。鉴于磷丝氨酸在细胞增殖、细胞信号传导和细胞死亡所必需的真核蛋白中的重要性，一种强有力的制备含磷丝氨酸蛋白的方法将具有广泛的应用和重要意义。本项目将为本科生和博士后提供跨学科的培训。

Synthesis of proteins containing amino acids outside of the genetic code has recently resurfaced as a topic of much interest and presents a great challenge intellectually and technically. Reprogramming the genetic code requires two key events: (i) The creation of a new efficient 'orthogonal' aminoacyl tRNA synthetase:tRNA pair able to generate solely a non canonical aminoacyl tRNA. (ii) The ability to specify the position in which this amino acid will be inserted in the protein by recoding a particular mRNA codon. Based on the natural existence of the recently discovered methanogen aminoacylsynthetase like protein, O-phosphoseryl tRNA synthetase and its cognate tRNACys research will be initiated to develop a prokaryotic and a eukaryotic system for the cotranslational insertion of phosphoserine at pre determined positions in a polypeptide based on the nonsense codon UAG in a messenger RNA. Given the importance of phosphoserine in eukaryotic proteins essential for cell proliferation, cellular signaling, and cell death, a robust method of making phosphoserine containing proteins will have wide application and great significance. This project will provide interdisciplinary training for undergraduate and postdoctoral students.