Functional synthetic enzyme could be catalyst for artificial life

Not content with editing the genes of living organisms or creating ever-smarter AI, scientists may eventually be able to biologically engineer unique artificial lifeforms from scratch. A new study from Princeton has brought that future a step closer, by confirming that an artificial protein the team developed functions as an enzyme in living bacteria. 

Over the years, the Princeton team has created artificial proteins for E. coli, a simple bacteria species that's commonly used as a testbed for these kinds of experiments. To test their creations, the researchers removed certain genes that resulted in the bacteria being unable to produce the enzyme Fes, which cells use to obtain iron. Without that vital mineral, the bacteria wouldn't be able to survive, but the team then plugged in proteins that could replace the missing function, "rescuing" or resuscitating the bacteria.

In the new study, the researchers have identified just how their new proteins work. They discovered that two of them keep the E. coli alive by compensating for the missing enzymes, boosting the production of other processes in the cell. But another of the proteins solved the problem more directly.

"This artificial protein, Syn-F4, was actually an enzyme," says Ann Donnelly, lead author of the study. "That was an incredible and unbelievable moment for me – unbelievable to the point that I didn't want to say anything until I had repeated it several times." Donnelly noticed that the cells were suddenly able to obtain iron, suggesting that Syn-F4 was an enzyme.