Meteorites Carrying Cyanide Could Have Given Ancient Life on Earth a Boost

By Korey Haynes | June 27, 2019 1:57 pm
illustration of asteroids striking early Earth
Meteorites are thought to have delivered many of the materials necessary for life, which might even include deadly cyanide. (Credit: NASA’s GSFC Conceptual Image Lab)

Science is still uncertain as to how exactly life first arose. While experiments with electricity and simple ingredients can make amino acids, the building blocks of proteins and the framework for all living things as we know them, how to make the jump from lifeless chains of molecules to biological life is still unknown.

Scientists want to understand how nature forms the more complex chains of molecules that are closest to what make up living creatures. The closer these molecules appear to those found in living creatures, the smaller a leap it takes to make life. This would put scientists on the right track to understanding how life came about.

One of the places scientists look for clues is early Earth, and the materials that would have been available then. Asteroids offer a time capsule of sorts of the kinds of materials that would have been around in the early solar system when Earth was young. By studying meteorites on Earth, scientists can gain an understanding of how our planet evolved — what materials were delivered ready-made to Earth, and which ones had to develop later, through chemistry or biology.

One odd chemical in some of these meteorites is cyanide. While most people are familiar with cyanide as a deadly poison, its components are simply carbon and nitrogen, both elements crucial to life. Recently, researchers at NASA and Boise State University studied a slew of meteorites, looking for traces of cyanide, and found some in a surprisingly useful form. They published their results June 25 in Nature Communications.

Poison or Life Giver?

Most surprising to the researchers was seeing how the cyanide was bonded to other materials in the meteorites. The result is very similar to hydrogenase, an enzyme crucial to life.

The idea is that if nature can – without the presence of life – produce something very similar to hydrogenase, then that leaves a much smaller gap to cross to create living things.

chemical diagrams
The compounds found in meteorites resemble parts of enzymes found in many bacteria. (Credit: Smith et al., 2019)

Karen Smith, lead author of the study, posits that molecules like those they found in the meteorites might have been later incorporated into proteins in living creatures. She goes on to muse that the similarity of the compounds in the meteorites and in living creatures, “makes you wonder if there was a link between the two.”

The particular meteorites researchers found bearing cyanide are a type known as CM chondrites. NASA’s OSIRIS-REx spacecraft is currently orbiting asteroid Bennu — likely also a CM chondrite — preparing to take samples that it will return to Earth in 2023. Its samples may teach astronomers more about where and how cyanide and other life-adjacent chemicals are distributed throughout the solar system, and perhaps one day show us how life came to be.

CATEGORIZED UNDER: Space & Physics, top posts
MORE ABOUT: solar system
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