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January 28, 2022

Meteorite phosphates may have powered life

By SAMHITA ILANGO | April 18, 2013

Could it be that the missing link between geology and biology has been discovered? Just ask Terry Kee, a reader at the University of Leeds in West Yorkshire, England. In his most recent study in the University’s chemistry department, Kee researches how non-living rock essentially converted into the building blocks of life.

With the general consensus being that some of the vital ingredients of life came from meteorites bombarding the early Earth, it is still a mystery as to how these rocks brought about life. Kee’s study centers on how a chemical could have been produced when meteorites containing phosphorous minerals landed in acidic pools of volcanic liquid. This chemical in particular is said to be similar to one found in all living cells and crucial to creating energy that makes something alive.

It is the process of chemiosmosis that powers the life on Earth and, more specifically, the chemical adenosine triphosphate (ATP) releases this energy that drives the reactions in life. ATP is claimed to be “the rechargeable chemical ‘battery’ for life.” Enzymes, biological molecules that catalyze biochemical reactions, are required for both the production and breakdown of ATP. However, it is highly unlikely that these enzymes existed on Earth before the first sign of life formation on Earth. Thus, scientists and researchers look for a more basic chemical with similarities to ATP, but do not entail enzymes to transfer energy.

Actually, phosphorous is the key element of ATP and other vital building blocks of life such as deoxyribonucleic acid (DNA). The common form of phosphorous on Earth is water soluble and has a low chemical reactivity. However, when the meteorites and interstellar dust landed on Earth, the form of phosphorous was much more reactive, an iron-nickel-phosphorous mineral called schreibersite.

For the study, scientists mimicked the impact of similar meteorites with hot volcanic liquids, similar to that of early Earth. They placed remnants of Sikhote-Alin meteorite, an iron meteorite that fell in Siberia in 1947, in acid taken from the Iceland Hveradalur geothermal area. The meteorite in the substance was left to react with the acid in test tubes incubated by a nearby hot spring for four days and subsequently placed in room temperature for 30 days.

After analysis, Kee and his associates discovered the compound pyrophosphite, which is related to pyrophosphate, the part of ATP that produces the energy transfer. They believe that this compound could have acted as an earlier structure of ATP claimed “chemical life.”

“Chemical life would have been the intermediary step between inorganic rock and the first living biological cell,” Kee said. “With the aid of primitive batteries, the chemical became organized in such a way as to be capable of more complex behavior and would have eventually developed into the living biological structures seen today.”

In addition, a team from NASA’s Jet propulsion Laboratory is working on the phosphorous question using the Curiosity rover. Recently, it has been reported that phosphorous is indeed present on Mars.

“If the Curiosity rover has found forms of phosphorous that we produced in Iceland, then conditions on Mars may be suitable for the development of life, similar to that of the development on Earth,” Kee said.

Now, the team at Leeds is working in collaboration with researchers at JPL-Caltech to understand how these early “batteries of life” might have transformed into biological life. They also hope to travel to Disko Island in Greenland, which sources schreibersite, the mineral found in the Sikhote-Alin meteorite. In the future, Kee and his team may repeat their experiment to show that the same chemicals develop in an “Earth-originated setting.”

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