英国医学研究委员会分子生物学实验室Chin, Jason W团队，通过自动正交mRNA设计使一个68个密码子的遗传密码包含四种不同的非标准氨基酸。相关研究成果发表在2021年8月23日出版的《自然—化学》。

正交（O）核糖体介导的O-mRNAs翻译使将多达三种不同的非标准氨基酸（NCAA）掺入大肠杆菌(E. coli)蛋白质中。然而，通过O-核糖体将多个不同的NCAA普遍而有效地结合，需要可扩展的策略来创建高效和特异性翻译的O-mRNAs，以及多个O-氨基酰基-tRNA合成酶（O-aaRS）/O-tRNA对的紧凑表达。

研究人员使O-mRNAs的发现自动化，与以前的O-mRNAs相比，O-mRNAs的蛋白质含量高达40倍，正交性高达50倍；该O-mRNAs的蛋白质产量与野生型mRNAs相当或超过野生型mRNAs。该进步使纳入三种不同NCAA的产量提高了33倍。研究人员自动创建O-tRNA基因的操纵子，并开发O-aaRS基因的操纵子。结合研究成果，研究人员创造了一个68个密码子、24个氨基酸的遗传密码子，有效地将四个不同的NCAA结合到一个蛋白质中，以响应四个不同的四重密码子。

附：英文原文

Title: A 68-codon genetic code to incorporate four distinct non-canonical amino acids enabled by automated orthogonal mRNA design

Author: Dunkelmann, Daniel L., Oehm, Sebastian B., Beattie, Adam T., Chin, Jason W.

Issue&Volume: 2021-08-23

Abstract: Orthogonal (O) ribosome-mediated translation of O-mRNAs enables the incorporation of up to three distinct non-canonical amino acids (ncAAs) into proteins in Escherichia coli (E. coli). However, the general and efficient incorporation of multiple distinct ncAAs by O-ribosomes requires scalable strategies for both creating efficiently and specifically translated O-mRNAs, and the compact expression of multiple O-aminoacyl-tRNA synthetase (O-aaRS)/O-tRNA pairs. We automate the discovery of O-mRNAs that lead to up to 40 times more protein, and are up to 50-fold more orthogonal, than previous O-mRNAs; protein yields from our O-mRNAs match or exceed those from wild-type mRNAs. These advances enable a 33-fold increase in yield for incorporating three distinct ncAAs. We automate the creation of operons for O-tRNA genes, and develop operons for O-aaRS genes. Combining our advances creates a 68-codon, 24-amino-acid genetic code to efficiently incorporate four distinct ncAAs into a single protein in response to four distinct quadruplet codons.

DOI: 10.1038/s41557-021-00764-5

Source: https://www.nature.com/articles/s41557-021-00764-5