The discovery supports the idea that many important building blocks of life may have formed together early on and combined to create living cells.
“Why do we have life? Why do the laws of chemistry mean that life here looks the way it does?” said Matthew Powner, senior author of “Why do we have life? Ta. research paper. These are “just the best questions we might be able to answer.”
Although living organisms look very different, they are made from the same basic chemical building blocks called primary metabolites, which are directly involved in cell growth and development. Examples include amino acids that help build proteins and nucleotides that make up RNA and DNA.
New laboratory experiments focused on the origin of another primary metabolite, coenzyme A. Coenzyme A is central to metabolism across all areas of life (as one of its many functions). For example, this compound plays an important role in releasing energy from carbohydrates, fats, and proteins in organisms that require oxygen, but also plays a metabolic function in organisms that do not require oxygen, such as many bacteria. I will fulfill it.
Specifically, Powner and his team were looking to recreate a specific fragment of the coenzyme A molecule called pantetheine. Pantetheine is the functional part of Coenzyme A, which is often transferred to allow other chemical reactions to occur in the body. This part is called a cofactor and acts as an “on” switch. Without this, coenzymes cannot be used.
“All of our metabolic processes depend on a small subset of these cofactors,” said biologist Aaron Goldman, who was not involved in the study. “This has led researchers to argue that these cofactors themselves may have existed before larger, more complex enzymes during the origin and early evolution of life. .”
According to Goldman, some researchers believe that early life forms used pantetheine to store energy before the larger, more complex energy currencies used by today’s cells evolved. He suggests that it is a possibility.
If so, the mystery remains as to where pantetheine came from.
“We can’t go back in time. We can’t go back to the origins of life. We can’t find samples from that period,” said Professor Powner from University College London. “The only possibility of getting to the bottom of that problem is to reframe it and start from scratch to redesign cells and understand what it takes to build an organism.”
Building Pantethein was a Herculean task. First, the molecule was “unusual” by biochemical standards. It closely resembled the structure of peptides (chains of amino acids) used to build proteins, but had many strange features (unusual elements in odd places) that seemed to give it a more complex structure. ) had.
This compound is such a strange duckling that scientists previously proposed that it was too complex to make from basic molecules. Attempts to create pantetheine failed, leading some to believe that pantetheine did not even exist at the origin of life. Many scientists thought that biology would have created a simple version of it and over time evolved to become more complex – for example, building a hut and later turning it into a mansion.
Nevertheless, the team headed to the lab. They primarily focused on using substances that may have been abundant on the early Earth, such as hydrogen cyanide and water. The first few steps of the reaction took about a day each, but the last step lasted his 60 days, making it the longest reaction Powner’s lab had ever conducted. The team eventually stopped responding “partly because we were tired of it,” he said. However, the results showed that there was more pantetheine.
The research team highlighted that their success, compared to failed studies by other researchers, lies in the use of nitrogen-based compounds called nitriles. These compounds provided much-needed energy to fuel reactions. Without nitrile, it’s like having a lawnmower but not having the gas to run it.
“I think it’s very surprising that no one has tried it. If you just mix all these together, they all react with each other,” said Jasper Fairchild, Ph.D. . candidate at University College London, who led the experiment. “You’d think it would be confusing, but it’s not. You just get pantetheine. And to me, that’s a very beautiful thing.”
On early Earth, this reaction may have occurred in small puddles or lakes, the authors said. But the concentration of chemicals would probably have been diluted in the wider ocean.
“This is another beautiful example of how molecules of life, and even more complex molecules like coenzymes, tend to form,” said Joseph, a chemist who was not involved in the study.・Moran stated.
A simple recipe for such a complex-looking molecule could rethink how life began on Earth. Historically, scientists have proposed that biological molecules emerge in stages, Powner said. RNA world It later produced proteins and other chemicals.
But the new findings suggest that many of the building blocks of life may have been produced simultaneously from the same basic chemicals and conditions, creating proteins, RNA and other components all at once. In fact, the team’s previous work used similar conditions and reactions to create nucleotides (which help make DNA) and peptides (which help form proteins). These building blocks may have come together and reacted with each other, ultimately leading to the origin of life.
A better understanding of how these building blocks form and fuse could one day help scientists create life from stationary matter in the lab or on another planet.
“We are far from being able to do it.” [from scratch] Make cells,” Powerner said. “It may not happen in my lifetime, but we are on the way to understanding how these molecules work together.”
This article is part of hidden planeta column that explores the surprising, unexpected, and quirky science of our planet and beyond.