Scientists obtained the Nickelback peptide, which consists of only 13 amino acids but can catalyze hydrogen oxidation. It is possible that such simple but effective proto-enzymes provided energy for the first truly living organisms on Earth.
At the most basic level, any organism is a region separated from the surrounding space where metabolic processes take place. It was with such protocells more than three and a half billion years ago that life on Earth began. Of course, they were extremely primitive, but they were able to carry out key metabolic reactions, which provided them with energy, the ability to reproduce and the like.
Hydrogen oxidation is thought to be one of these reactions. There was much more of it on the young Earth than there is today, and it may well have been a source of energy for newborn life. Some bacteria and archaea still use hydrogen for this purpose today, oxidizing it with oxygen, sulfate, carbon dioxide and other suitable substances. Such reactions are catalyzed by hydrogenase enzymes.
Most likely, hydrogenase precursor molecules were present in the earliest protocells as well. But while modern microbes have large, complex proteins containing hundreds of amino acids and various cofactors, at the beginning of life they were much simpler. A team of scientists at Rutgers University managed to identify such a "minimal hydrogenase.
Laboratory Vikas Nanda (Vikas Nanda) - a key site for large-scale research project ENIGMA, whose members are trying to identify a "minimal set of minimal proteins," which can provide a transition from prebiotic reactions to the real biology and the emergence of life. To find such a hydrogenase, scientists analyzed the structures of existing enzymes today and performed computer simulations, getting rid of "everything superfluous".
As a result, they obtained a short peptide containing only 13 amino acid residues and two nickel atoms coordinated with them. The authors called this molecule Nickelback. Laboratory experiments showed that such peptides can spontaneously assemble under suitable conditions, remain stable, and exhibit catalytic activity in hydrogen oxidation. It is possible that it was from such primitive molecules that the complex, multicomponent proteins of modern organisms originated. But at first, young life relied on them.