by A small protein molecule that scientists said is one of the most likely chemical candidates to fuel life has been identified by them in an advance that could provide clues to the discovery of habitable planets beyond Earth.
The results recently published in the journal scientific advanceshave important implications for the search for extraterrestrial life as they give scientists a new lead to look for.
Researchers, including those from Rutgers University in the US, found that a simple peptide molecule containing two nickel atoms is one of the most likely molecules to have sparked life on Earth.
They named the short protein molecule “Nickelback” because its nitrogen atoms in the backbone combine with two nickel atoms.
“Scientists believe that sometime between 3.5 and 3.8 billion years ago there was a tipping point, something that ushered in the shift from prebiotic chemistry — molecules before life — to living, biological systems,” said Vikas Nanda, co- author of the study, in a statement.
“We think the change was triggered by a few small precursor proteins that performed key steps in an ancient metabolic reaction. And we think we’ve found one of those “pioneer peptides,”” said Dr. nanda
In the study, scientists hoped to understand how proteins evolved to become the dominant catalyst of life on Earth.
The research can help astronomers look for signs of past, present or emerging life, as well as specific life signature molecules in other parts of the universe.
The researchers argued that a primordial chemical to trigger life would have to be simple enough to spontaneously assemble in early Earth’s waters, but the chemical also had to be sufficiently reactive.
They began by examining existing contemporary proteins known to be associated with metabolic processes and reduced them to their basic structure.
Scientists found that the best candidate was nickelback – a 13-amino acid peptide that binds two nickel ions – because the element nickel was also abundant in Earth’s early oceans.
When attached to the peptide, the nickel atoms become potent catalysts, the researchers said.
“This is important because while there are many theories about the origin of life, there is very little actual laboratory testing of these ideas. This work shows that not only are simple protein-metabolizing enzymes possible, but that they are very stable and very active – making them a plausible starting point for life,” added Dr. added nanda
