15.02.10
Researchers extend genetic code to produce artificial proteins
Cambridge – British researchers have extended the genetic code of bacteria to produce artificial proteins with improved properties, as published in Nature, Feb. 14. A team led by Jason Chin from Cambridge University redesigned the cell’s protein synthesis factory (the 16S subunit of the ribosome) to incorporate 200 amino acids with novel chemical features into the growing protein chain instead of only 20 naturally ocurring protein building blocks. Instead of 3 letters of the genetic code, the redesigned Ribo-Q1-ribosome can recognize 4 letters. This opens up the possibility to link synthetic amino acids, which do not occur in nature, to the extended 4-letter-codes (quadruplet codons). Using their novel genetic code, the synthetic biologists genetically redirected the formation of proteins for the protein Calmodulin to incorporate artificial amino acids with azide and alkyne functions, which then formed redox-insensitive protein cross-links. According to the researchers, their new approach opens up the design of proteins with higher stability due to the novel kind of chemical cross-link. This extended genetic code, together with the novel ribosome, lays the groundwork for the synthesis and synthetic evolution of non-natural polymers in bacterial cells.