In this study, researchers are designing and building proteins that can fold and mimic the chemical processes that sustain life. Now they have confirmed that at least one of their new proteins can catalyze biological reactions in E. coli, meaning that a protein designed entirely from scratch functions in cells as a genuine enzyme. The study published the paper in Nature Chemical Biology.
Hecht and his colleagues have confirmed that at least one of their new proteins can catalyze biological reactions, meaning that a protein designed entirely from scratch functions in cells as a genuine enzyme. Their artificial proteins, encoded by synthetic genes, are approximately 100 amino acids long, using an endlessly varying arrangement of 20 amino acids.
Enzymes are key to all of biology, Hecht said. "Biology is the system of biochemical reactions and catalysts. Each step has an enzyme that catalyzes it, because otherwise those reactions wouldn't go fast enough for life to exist. Enzymes can increase the speed of a reaction by many orders of magnitude."
They found four genes that, when removed, would not only render the E. coli inert — effectively dead — but which their artificial proteins could then "rescue," or resuscitate. She only told Katie Digianantonio, "I said, 'I think this is an enzyme.' I showed them the initial data and said, 'Don't say anything to Michael. Let me do this again." Donnelly re-purified the protein, and created a new, perfectly pure substrate for the E. coli.
"Biotechnology commonly uses enzymes to carry out industrial processes to produce materials, food, fuel and medicine," Siegel said. "The use of these enzymes in an industrial setting often starts with an enzyme that nature evolved for billions of years for an unrelated purpose, and then the protein is tweaked to refine its function for the modern application.
Hecht's team had created a strain of E. coli that was missing the enzyme Fes, without which it cannot access the iron needed to sustain life. "We all need iron," Hecht said. "Even though iron is abundant on earth, biologically accessible iron is not." This modified E. coli strain had no way to extract, or hydrolyze, the iron from its enterobactin, until it was "rescued" by Syn-F4.
The researchers had provided iron to the E. coli, but it only stained the cells red, since although they could accumulate the bound metal, they could not liberate it from enterobactin or access it for cellular use.
Author declines that they started to code for an artificial genome and rescued 0.1 percent of the E. coli genome. For now, it's a weird E. coli with some artificial genes that allow it to grow. Suppose you replace 20%. Then it's not just a weird E. coli with some artificial genes, then you must say it's a novel organism.