How were the first cells formed? with protein

New research shows that the building blocks of proteins are able to stabilize the fatty acids that build the cell membrane, and thus could help in the creation of the world's first living cells

What is the recipe for creating a living cell?

We need small machines, molecules that will do the necessary jobs: breaking down food, producing energy, dividing a cell, creating more small machines. These are the proteins. We need molecules that will contain the information needed to build these machines. These are the nucleic acids, the hereditary material of the cell. But just as important, we need the cell to have "walls" - a boundary that will separate it from its environment, and maintain within it suitable conditions for the actions of proteins and nucleic acids. The cells of all living things, from a bacterium to a whale or a petunia, are surrounded by a membrane made of a double layer of fatty acids, separating the internal environment of the cell from the outside world. Without that membrane, no cell is possible, and no life is possible.

The prevailing hypothesis is that the first, earliest living things were nothing more than a fatty membrane that surrounded some simple proteins and short nucleic acids. But how did those proto-cells, the simple structures that preceded the cells we know today, form? What caused their various components to cluster together? There are quite a few hypotheses that try to answer this, and explain how life first appeared, but we still do not have a clear and agreed upon answer for all of them.

The creation of the cells themselves, those tiny "sacks" made of fatty acids, is actually not complicated. Fatty acids found in water arrange themselves naturally, without the need for an external push, in a sort of small spheres surrounded by a membrane. But these membranes are unstable, and break down when they are in the presence of various salts. This is quite a serious problem. First, the water in the ancient oceans, where life evolved, was rich in salts. Apart from this, various salts and ions are needed for the actions carried out inside the cell. If the membrane breaks down under these conditions, a functioning cell cannot form.

A moment of "Aha!"

In a new study, researchers from the United States offer a solution for this: they discovered that some amino acids - the small molecules from which proteins are built - stabilize the membranes. In the presence of these amino acids, the small balls wrapped in the membrane maintain their shape even in a salt environment. This fact can explain not only how those not-quite-first cells were formed, but also the presence of proteins, or at least their building blocks, within the proto-cells.

The amino acids used by the researchers can also be formed without life, in simple chemical processes. The researchers added them to a salt solution containing fatty acids, and when they looked under a microscope they saw the small balls floating in the solution, with the amino acids stabilizing them and preventing them from breaking down. "We were really excited," Sarah Keller, who led the study, told The Atlantic. "It was an 'Aha!'"

Keller and her colleagues still do not know how the amino acids stabilize the fatty membranes. "We have no idea, because it's not something we expected to happen," Keller said. "We're in this great place, which opens up the field for future theories."

According to one hypothesis, life first arose in shallow pools, which dried up and filled again and again. The researchers point out that under such conditions a high concentration of amino acids can be created, which will lead to the creation of stable protocells. And within those proto-cells there will already be an abundance of amino acids, the building blocks of the proteins that are so important to living cells.

The next study by Keller and her colleagues focuses on this phase. We have cells, and there are simple molecules in them - but what happens now? "How do those individual building blocks bond to form larger molecules?" Keller presented the problem. "That's a very difficult question."

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More of the topic in Hayadan:

• In the beginning the sea was acidic
• From the creation of the universe to the creation of life
• How did life come about?