Scientists create first semisynthetic 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 “semisynthetic” 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