Scientists have identified a small protein molecule that they say is one of the most promising chemicals thought to be the beginning of life and could hold the key to the discovery of habitable planets beyond Earth.
The team says the results, recently published in the journal Science Advances, are important to the search for extraterrestrial life as they give scientists new evidence to look for.
Scientists, including researchers at Rutgers University in the US, have discovered that a simple peptide containing two nickel atoms is one of the molecules most likely to fuel life on Earth.
They named the short protein molecule Nickelback, which is made up of nitrogen atoms bonded to a main conductor with two nickel atoms.
“Scientists believe that somewhere between 3.5 and 3.8 billion years ago, a tipping point occurred that initiated the transition from prebiotic chemistry – prebiotic molecules – to living biological systems,” study co-author Vikas Nand said in a statement.
“We think this change was caused by several small precursor proteins that made key steps in an ancient metabolic response. We think we’ve found one of the leading peptides.”
In this study, the scientists hoped to understand how proteins evolved to become the main contributors to life on Earth.
The research could help astronomers look for signs of past, present, or emerging life, as well as specific molecules for signatures of life elsewhere in the universe.
The team concluded that the original chemical that ignited life must have been simple enough to spontaneously collect in early Earth’s waterways, but it must also have been reactive enough.
They started by studying existing modern proteins that are known to be involved in metabolic processes and reconstructed their basic structure.
Scientists have found that the best candidate is nickelback, a 13-amino acid peptide that links two different nickel atoms. Nickel was also abundant in early Earth’s oceans.
The team said that when the nickel atoms bind to the peptide, they become powerful catalysts.
This means that such a structure is simple enough for the formation of organic molecules and is stable under conditions of extreme temperatures and high acidity, which could contribute to the emergence of life.