For many decades, scientists have puzzled over howhow life began on earth. And despite the fact that many processes are already clear, there is still no exact answer to this question. However, it is believed that metabolism, that is, the ability to produce a chemical reaction and thus extract the energy necessary for the internal processes that ensure life, has become the brink of the transition from inanimate to living. There is no doubt that the molecule that first produced the metabolic reaction was simple, as it arose from the components that were present in the water. At the same time, the reaction itself was quite effective, which allowed it to give rise to colossal changes in the environment. It seems that now scientists have even managed to find out what the first metabolic reaction was, and what molecule produced it.
The protein that may have given rise to biological life is called Nickelback, but not after a rock band
How life began
According to scientists, the transition from prebioticchemistry, that is, inanimate molecules preceding life, to biological systems occurred 3.5-3.8 billion years ago. Earlier we said that the most ancient forms of life most likely originated as a result of the interaction of metals and proteins.
Now a team of scientists from Rutgers University andCity College of New York in the United States discovered a protein that apparently gave impetus to the emergence of life. It is a simple peptide called nickelback. We say right away that the name has nothing to do with the Canadian rock band Nickelback, but only reflects the structure of the protein.
Schematic drawing of a nickelback protein that has two nitrogen atoms (blue) and two nickel atoms
A peptide is made up of amino acids, also a pair of atomsnitrogen, which are bonded to nickel atoms. Nickelback could be the first to produce a metabolic reaction, as a result of which, in fact, it became a transitional element from inanimate to living. Subsequently, the evolution of protein structures led to the emergence of life in the usual sense of the word for us.
What was the first "live" protein
To find out what was the first protein that gavethe beginning of life on Earth, researchers began their work by studying modern proteins that reproduce metabolic processes. However, ancient proteins were much simpler than modern ones, so they were broken down into separate components.
As a result of many experiments, scientistsfound that nickelback is an ideal candidate for the role of the very first protein with a metabolism. Since it is quite simple, it could well have arisen under the conditions that existed on Earth 3.8 billion years ago. At the same time, nickelback is able to take energy from the environment.
Nickel is the metal that may have provided ancient proteins with metabolism
Protein contains 13 essential amino acids, whichcommonly referred to as the "bricks" of life. In this case, two nickel atoms could ensure the activity of the nickel-iron group in hydrogenase (NiFe). Hydrogenases are enzymes that catalyze the reversible oxidation of molecular hydrogen. Hydrogenases are found in bacteria, archaea, and some eukaryotes. In addition, nickel ensured the activity of the nickel-nickel cluster in acetyl-CoA synthase. These molecules still play an important role in metabolism to this day.
Simply put, it was nickel atoms that providedpeptide by a chemical reaction that made it possible to extract energy from hydrogen, which at that time was a key source of energy. The team was able to replicate all of these processes in the lab, which they report in the journal Science Advances. Thus, the results of this study correlate with the aforementioned study, in which it was argued that metals and proteins provided the basis for life.
Nickel was present in abundance on Earth 3.8 billion years ago
It must be said that nickel was commonmetal in the ancient oceans of the Earth. And if he played a key role in the origin of life on our planet, then, quite possibly, he could form life on other planets that have not yet evolved. By the way, the evolution of the first bacteria into advanced life occurred by pure chance. Theoretically, life on Earth to this day could remain in the form of simple bacteria.
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Of course, the basis of life is not onlymetabolism, but also the two main forms of the genetic code, the DNA and RNA molecules. Scientists suggest that they could exist on Earth even before the appearance of life. It is quite possible that RNA was brought to our planet with meteorites, or rather their components. Not so long ago, indirect evidence was found for this.