Friday, March 1, 2024

Science: Regarding the origin of life on Earth

The WaPo writes (not behind paywall) about another step in the quest to understand how life evolved out of non-life on Earth. This is an interesting discovery of the spontaneous creation of an important complex molecule (pantetheine) that scientists did not believe would exist if life had not evolved. 

The new lab experiment focused on the origins of another primary metabolite: coenzyme A, which sits at the heart of metabolism across all domains of life (as one of its many functions). For instance, the compound plays a vital role in releasing energy from carbohydrates, fats and proteins in organisms that require oxygen, but it also serves metabolic functions in lifeforms that don’t need oxygen, like many bacteria.

Specifically, Powner and his team were looking to re-create a particular fragment of the coenzyme A molecule called pantetheine. Pantetheine is the functional arm of coenzyme A, often getting transferred and enabling other chemical reactions in our body to occur. This limb is called a co-factor and acts as an “on” switch — without it, the coenzyme would be unusable.



CoA (coenzyme A)


“All of our metabolic processes rely on a small subset of these co-factors,” said biologist Aaron Goldman, who was not involved in the study. “This has led researchers to argue that these co-factors, themselves, may have predated larger, more complex enzymes during the origin and early evolution of life.”

Some researchers, Goldman said, have proposed that early lifeforms could have used pantetheine to store energy before the evolution of the larger, more complex energy currency that cells use today.

If this is the case, the mystery stood: Where did pantetheine come from?

The compound is such an odd duckling that scientists previously proposed it was too intricate to make from basic molecules. Others have tried to create pantetheine and failed, thinking that it wasn’t even present at life’s origins. Many scientists thought biology would have created a simple version of it, which would have evolved to become more complicated over time — like building a shack and later turning it into a mansion.

The team took to the lab. They focused on primarily using materials that could have been abundant on early Earth, like hydrogen cyanide and water. The first few steps of the reaction each took about a day, but the final step lasted 60 days, which was the longest reaction that Powner’s lab has ever done. The team finally shut off the reaction “partly because we got bored,” he said. But the result was a lot of pantetheine.

Pantetheine
The experts did not think this could
form without life to create it
The experts were wrong

I see this as a major advance in explaining how life could arise on Earth from non-life. It took time. After just 60 days of waiting and finally getting impatient, the scientists stopped the experiment. They looked and found spontaneous synthesis of the complex molecule pantetheine from simple building blocks and water. 60 days is nothing. Think in terms of 600 million years. 

I can now much more clearly envision how life arose from non-life on Earth. Stable climate, lots of water and millions of years for chemical reactions. This is more evidence suggesting that is how life arose here. Not from God, but from chemistry under the right conditions for a heck of a long time.

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