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Alien organism created by adding new letters to the genetic alphabet could lead to more effective designer drugs
Synthetic DNA made in lab, interstellar asteroid captured entering the Solar System, Stretchy sweat-powered battery made out of fabric…
A team of scientists at the Scripps Research Institute in the US have created a living ‘semi-synthetic’ organism capable of producing proteins never seen before on Earth by adding new letters to the genetic code. The synthetic proteins created by such organisms could pave the way for a new generation of made-to-order drugs and therapies, the team said.
The regular genetic ‘alphabet’ consists of four letters, or bases: A, T, G and C. These stand for adenine, thymine, guanine and cytosine, which are the four chemicals that make up DNA. These letters can combine in different sequences to form 20 naturally occurring amino acids – the building blocks of proteins.
In 2014, the Scripps team created two more ‘letters’, X and Y, making it theoretically possible to create a further 152 synthetic amino acids. However, they were unable to make an organism that could produce proteins. Now, they have successfully created an organism capable of producing so-called green fluorescent proteins by modifying Escherichia coli – a single-celled, rod-shaped bacterium commonly used in the lab-based manufacture of proteins.
“This is the first time that proteins have been produced in any cell by the decoding of a six-letter genetic alphabet, instead of just the natural four-letter alphabet,” said study leader Dr Floyd Romesberg. “The limited combinations of the natural DNA bases, A, T, G, and C, have restricted the types of new protein therapeutics that could be made. Adding X and Y to the genetic alphabet, we now have an expanded vocabulary to be able to generate a variety of new proteins that might be developed for a wide range of applications, including as new therapeutics.”
It was previously believed by many researchers that our specific DNA structure was essential for the evolution of life. However, the breakthrough by the Scripps team opens up the possibility that life could have evolved in a different way on another planet.
The organism is completely safe and has no chance of spreading out beyond the lab and contaminating natural life forms as it is incapable of producing the X and Y bases it needs to live by itself, the researchers said.