The history of life on Earth is so intricate that, although today we more or less understand the evolution of such complex organisms, we have not yet been able to detect the moment of chemical to biological transition on the planet.
Scientists believe that sometime between 3.5 and 3.8 billion years ago, a turning point occurred in which prebiotic chemistry transitioned into living biological systems, leading to the origin of life. However, the chemical processes that triggered the metabolic reaction that finally gave rise to what could be said were the first living entities are unknown.
The origin of life
Scientists at the University of New Jersey have conducted a study to better understand the reaction that gave rise to life. They analyzed different designs of modern peptides and proteins that are currently known to drive metabolic processes crucial for life, thus they found a candidate that could have triggered the origin of life, which they called Nickelback. This peptide refers to the backbone of the protein, which consists of a chain of amino acids and two nitrogen atoms bonded to a pair of nickel atoms. “We think the change was caused by a few small precursor proteins that performed key steps in an ancient metabolic reaction.
And we believe that we have found one of these pioneering peptides,” the authors explain in their article published in Science Advances. To get to the Nickelback peptide as the basis for the origin of life, researchers began by analyzing modern proteins that are known to play an important metabolic role in modern life. Unlike today’s proteins, the oldest peptides must have behaved much more simply, which is why the team broke them down into their most basic parts to analyze them.
This is how they found that Nickelback is a candidate simple enough to form on a prebiotic Earth, but is also complex enough to take energy from the environment and produce metabolic reactions. Nickelback uses a total of 13 amino acids, which are ‘building blocks’ by which proteins are built and therefore are also an essential component for life; Two nickel atoms are joined to this chain to form proteins with the metabolic power to form life.
According to what is known from a very ancient Earth, nickel would have been an abundant metal present in the first oceans. The researchers demonstrated in the laboratory that when nickel atoms bind to the Nickelback peptide, they act as a catalyst in the release of hydrogen gas, an element that would have been a vital source of energy billions of years ago.
“This is important because, while there are many theories about the origins of life, there is very little actual laboratory testing of these ideas,” says Vikas Nanda of the University of New Jersey and co-author of the study.
This story was written in Spanish by Alejandra Martinez in Ecoosfera