Scientists create first semi-synthetic organism that stores, retrieves info
LA JOLLA, California: Some 3.5 billion years ago, life on Earth evolved to have just four “letters” in its genetic code. These letters are the DNA bases G, C, A and T – and they spell out the instructions for making proteins in every organism on Earth.
But scientists in a lab at The Scripps Research Institute (TSRI) have been working on something new. They’ve designed a bacterium with two unnatural bases, called X and Y, which could someday help them produce new molecules for medical therapies.
In a study published in the journal Nature, the researchers announced that their “semi-synthetic” strain of E. coli is the first to both contain the unnatural bases in its DNA and use the bases to instruct cells to make a new protein.
“I would not call this a new lifeform – but it’s the closest thing anyone has ever made,” said TSRI Professor Floyd Romesberg, who led the study. “This is the first time ever a cell has translated a protein using something other than G, C, A or T.”
The new research builds on the Romesberg Lab’s previous efforts to expand the limited “alphabet” of natural DNA.
The protein produced in this process was a variant of green fluorescent protein (GFP), a naturally glowing marker often used in genetic experiments, which contained different unnatural amino acids incorporated at a selected site.
“This was the smallest possible change we could make to the way life works – but it is the first ever,” said Romesberg. — Newswise