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Every life form on Earth uses the same chemical for energy. This may explain why. : Science Alert

Every life form on Earth uses the same chemical for energy.  This may explain why.  : Science Alert
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All life as we know it uses the same energy-carrying molecule as a kind of “universal cellular fuel”. Now ancient chemistry can explain how this important molecule turns out to be ATP (adenosine triphosphate). reports.

ATP is an organic molecule that is replenished and used in every cell by photosynthesis or cellular respiration (the way organisms break down food). Every day we recycle our own body weight into ATP.

In both of the above systems, a phosphate molecule is added to ADP (adenosine diphosphate) through a reaction called phosphorylation, resulting in ATP.

Reactions that release the same phosphate (in another process called hydrolysis) provide chemical energy that our cells use for countless processes, from brain signaling to movement and reproduction.

How ATP rose to metabolic dominance over its many possible equivalents has long been a mystery and the focus of research in biology.

“Our results show that the emergence of ATP as the cell’s universal energy currency is not the result of a ‘frozen accident’, but rather a unique interaction of phosphorylating molecules.” you explain Nick Lane, an evolutionary biochemist from University College London (UCL).

The fact that ATP is used by all living things suggests that it has existed since the beginning of life, and even before that, in prebiotic conditions that predate us all.

But researchers wonder how this can be when ATP has such a complex structure, involving six different phosphorylation reactions and a lot of energy to create it from scratch.

There is nothing special about “high energy”. [phosphorus] bonds in ATP,” say biochemist Silvana Pinna, then with UCL, and colleagues. in their paper.

But because ATP also helps make our cells’ genetic information, it can be used for energy use via another pathway, they note.

Pinna and team suspect that some other molecule is involved first in the complex phosphorylation process. So they took a closer look at another phosphorylating molecule, AcP, which is still used by bacteria and archaea in the metabolism of chemicals, including phosphate and thioester. early in life.

In the presence of iron ions (Fe3+), AcP can phosphorylate ADP to ATP in water. Researchers testing the ability of other ions and minerals to catalyze ATP formation in water were unable to replicate this with other replacement metals or phosphorylating molecules.

“It was surprising to discover that the reaction was so selective in the metal ion, the phosphate donor, and the substrate—molecules that life still uses.” he says pinna

“It’s really important for the origin of life that it happens best in water under mild, life-friendly conditions.”

This suggests that these energy storage reactions with AcP may have occurred under prebiotic conditions, before there was biological life to harvest and drive the now self-perpetuating cycle of ATP production.

In addition, experiments show that the creation of prebiotic ATP can occur in freshwater, where, for example, photochemical reactions and volcanic eruptions can provide the right mix of ingredients, the team explains.

While this does not completely rule out a marine origin, it does indicate that life may have required a strong connection to land for its birth, they note.

“Our results suggest that ATP has evolved as a universal energy currency in a prebiotic, monomeric world based on its unusual chemistry in water,” Pinna and colleagues write.

Moreover, pH gradients in hydrothermal systems can create an unequal ratio of ATP to ADP, allowing ATP to function even in the prebiotic world of small molecules.

“Over time, with the advent of suitable catalysts, ATP can eventually displace AcP as the ubiquitous phosphate donor and promote the polymerization of amino acids and nucleotides to form RNA, DNA, and proteins.” you explain Strip.

This study was published PLOS Biology.

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