Chemists from rice University in the US, have cracked the genetic code of Escherichia coli with the introduction of the mechanism of protein synthesis is an additional amino acid. As a result, the bacterium is a live indicator of oxidative stress. This was reported in the article Chem.
As a rule, living organisms are used for the construction of proteins 20 different amino acids that are encoded by combinations of three nucleotides (codons) in DNA. Scientists have been forced E. coli to use the amino acid hydroxytryptophan (5HTP), which in humans serves as a precursor to the neurotransmitter serotonin. Bacteria 5HTP started to be a part of a protein that fluoresce in a state of metabolic stress.
Change the genetic code consisted of three stages. First, scientists have developed a biochemical translational mechanism that allows the cell to incorporate 5HTP in the protein. This mechanism is biorthogonal, that is, it does not interfere with natural biochemical processes and does not violate the normal process of translation, where genetic information about the structure of normal proteins is transferred to the ribosomes, where the proteins are synthesized. Second, for encoding 5HTP has been used “blank” codon — sequence of three nucleotides that is not “fixed” for a particular amino acid. Finally, bacteria were inoculated enzymes necessary for the production of the most 5HTP.
To date, scientists worldwide have created more than 200 non-canonical amino acids, but most of them cannot be synthesized by living organisms. The introduction of additional amino acids allows researchers to monitor cells and their reactions to the environment. The researchers hope that in the future the ability of the living organism itself to produce artificial molecules will allow to therapeutic drugs in the right quantities. For example, the modified tumor cells can produce anti-tumor molecule, stopping the development of cancer.
