The genetic code in most organisms codes for 20 proteinogenic amino acids or translation stop. In order to encode more than 20 amino acids in the coding system, one of stop codons is usually reprogrammed to encode a non-proteinogenic amino acid. Although this approach works, usually only one amino acid is added to the amino acid repertoire. In this study, we incorporated non-proteinogenic amino acids into a protein by using a sense codon. As all the codons are allocated in the universal genetic code, we destroyed all the tRNAArg in a cell-free protein synthesis system by using a tRNAArg-specific tRNase, colicin D. Then by supplementing the system with tRNACCU, the translation system was partially restored. Through this creative destruction, reprogrammable codons were successfully created in the system to encode modified lysines along with the 20 proteinogenic amino acids. tRNAArg-specific tRNase, colicin D, affects no other components of a cell-free protein synthesis system but leaves six blanks in the genetic code. These can be redirected for the incorporation of non-proteinogenic amino acids by genetic code reprogramming techniques.

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sense codon genetic code reprogramming amino acids trnaargspecific trnase translation system cellfree protein synthesis system modified

Chen Yuan Hou, Taek Jin Kang, Dong-Myung Kim, Chae-Eun Kim, Hiroaki Suga,Ki Baek Lee,.Genetic Code Expansion by Degeneracy Reprogramming of Arginyl Codons. 17 (13),1201-1198.

Chen Yuan Hou, et al."Genetic Code Expansion by Degeneracy Reprogramming of Arginyl Codons" 17

Chen Yuan Hou, Taek Jin Kang, Dong-Myung Kim, Chae-Eun Kim, Hiroaki Suga,Ki Baek Lee,"Genetic Code Expansion by Degeneracy Reprogramming of Arginyl Codons"