NASA Scientists Resurrect Ancient Enzyme to Validate Biosignature for Life

The research provides new insights into early life on Earth and could aid the search for ancient life on other planets.

Jan. 30, 2026 at 9:39am

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NASA-supported scientists have resurrected an enzyme first used by organisms on Earth 3.2-billion years ago and, in the process, have validated a chemical biosignature in rocks that is used to understand ancient life on Earth. The research provides a new understanding of what Earth's biosphere was like early in our planet's history and confirms a reliable biosignature that could be used by robotic or human explorers to look for signs of ancient life on other worlds.

Why it matters

This research is important because it helps validate the use of nitrogen isotopes as a reliable biosignature for detecting signs of ancient life, not just on Earth but potentially on other planets as well. Understanding the evolution of critical metabolic processes like nitrogen fixation provides insights into the early conditions that supported life on our planet and could inform the search for life beyond Earth.

The details

The study focused on a type of metabolism called nitrogen fixation, which converts biologically unusable nitrogen in Earth's atmosphere into molecules that all living organisms use to survive. The researchers used synthetic biology techniques to resurrect possible ancient versions of the nitrogenase enzyme responsible for nitrogen fixation. By observing the behavior of these older enzyme versions, they found that the nitrogen isotope signatures have remained the same for billions of years, proving that the isotopic signatures in Earth's oldest rocks do indeed reflect the activity of early life.

  • The study was published in Nature Communications on January 22, 2026.
  • The researchers resurrected an enzyme first used by organisms on Earth 3.2-billion years ago.

The players

Betül Kaçar

Leads the Kaçar Lab at the University of Wisconsin-Madison and is working to understand the history of life at a planetary scale and the potential for life in the universe by rebuilding extinct biochemistries used by ancient organisms.

Holly Rucker

A doctoral candidate in the Kaçar Lab and lead author on the paper.

Nitrogenase

An enzyme that gives certain organisms the power to convert nitrogen gas from the atmosphere into compounds that are essential for building some of life's most important molecules, such as proteins and DNA.

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What they’re saying

“Early life on Earth operated under conditions so different from today that it may have appeared almost alien.”

— Betül Kaçar, Researcher (NASA.gov)

“As you step back in time, the DNA sequences of these ancient nitrogenases are very different than modern nitrogenases. We also see that the enzyme structure varies with age. Yet we find that despite these sequence and structure-level differences, these ancient enzymes still do the same chemistry as their modern descendants.”

— Holly Rucker, Doctoral Candidate (NASA.gov)

What’s next

The collection of synthetic genes created by the team represents different versions of nitrogenase that would have existed over a span of two billion years of evolutionary history. This has helped fill in gaps of knowledge about how nitrogenase has changed over time, and what ancient nitrogen fixers were like. The researchers plan to continue studying these ancient enzymes to further understand the early conditions that supported life on Earth and how that knowledge could inform the search for life beyond our planet.

The takeaway

This research provides valuable validation of nitrogen isotopes as a reliable biosignature for detecting signs of ancient life, not just on Earth but potentially on other planets as well. By resurrecting and studying ancient versions of the critical nitrogenase enzyme, the researchers have gained new insights into the evolution of life's fundamental metabolic processes, which could aid in the search for extraterrestrial life.