Scientists identify possible chemical reaction triggering life on Earth

In Earth's early history, there was a critical point where chemical reactions between a mixture of organic molecules began to be fueled internally. This resulted in the formation of something that could be considered biological, although the exact appearance of the first metabolic reaction remains the subject of speculation.

It must have been a simple enough entity to emerge from the various components that probably were present, but still efficient enough to catalyze changes in your environment.

A protein callednickelback", one peptide simple with a backbone consisting of a chain of amino acids and two nitrogen atoms bonded in a pair of nickel atoms, was identified by researchers from Rutgers University and the City College of New York, in the USA. This discovery may have played a crucial role in the creation of life as we know it, shedding more light on how life began here on Earth.

Furthermore, it could help astronomers in their search for life on other planets that contain these essential chemical ingredients just beginning to form. Therefore, this is not a tribute to the famous Canadian rock band, but rather an important scientific discovery.

Biochemist and molecular biologist Vikas Nanda of Rutgers University in New Jersey explains that there are about 3.5 to 3.8 billion years ago there was a tipping point in the shift from prebiotic chemistry to biological systems alive. Scientists believe this change was triggered by small precursor proteins that carried out key steps in an ancient metabolic reaction. And, according to Nanda, one of these pioneering peptides has been found.

To arrive at this result, scientists started with modern proteins that power metabolic processes crucial in driving biochemical reactions. From there, ancient proteins were broken down into their most basic parts and experiments produced nickel as a likely candidate.

This peptide is made up of 13 amino acids, which are often described as the “building blocks” for proteins and for life itself. Furthermore, the basic activity of the nickel-iron group in hydrogenase [NiFe] and the nickel-nickel cluster in acetyl-CoA synthase could be mirrored by the two nickel atoms attached to the basic scaffold, two ancient proteins that still play important roles in metabolism today.

Nickel atoms, abundantly present in Earth's first oceans, act as catalysts in the release of hydrogen gas when bound to the peptide, a vital source of energy billions of years back. The processes involved have been proven in the laboratory by a team of researchers from Rutgers University and the City College of New York, in the USA.

Nanda says that the existence of laboratory tests is crucial, because although there are many theories about the origins of life, there are few actual tests of these ideas. If nickelback was significant in early life on Earth, it could be forming on other planets as well. Nickel could be added to the list of biosignatures used by researchers to search for life further afield in the Universe.

Looking back into the history of life on Earth, clever techniques allow us to work backwards from today to understand how complex life formed in the first place. Nanda concludes that simple protein metabolic enzymes are not only possible, but also very stable and active, making them a plausible starting point for life.