Researchers have reconstructed a nitrogen-fixing enzyme from more than three billion years ago using synthetic biology. The work offers new insights into how life evolved on early Earth and could inform searches for life elsewhere in the universe.
Scientists at Utah State University and the University of Wisconsin-Madison rebuilt ancestral versions of nitrogenases, enzymes that convert atmospheric nitrogen into a form usable by living organisms. The study, published in Nature Communications, examined how these enzymes may have functioned billions of years ago.
Lance Seefeldt, a biochemist at Utah State University, noted that all living organisms need nitrogen to survive yet cannot access it directly. "Enzymes called nitrogenases enable nitrogen fixation," he said. The team measured nitrogen isotope fractionation in engineered strains to compare ancient and modern versions.
Betül Kaçar, who leads the NASA-funded MUSE project, said the findings help explain conditions on early Earth before oxygen-dependent life emerged. She added that understanding the planet's past is essential for identifying life on other worlds.
The research may also support efforts to improve agriculture in drought-prone areas and to grow food in space.
