A substance that may offer clues in the search for extraterrestrial life has been discovered by a team of scientists from Rutgers University.
Dubbed the “pioneer peptide,” the identified part of a protein could be invaluable in determining which planets are on the verge of producing life, according to research published in Science Advances.
'Catalyst of Life'
The team of researchers, all part of the Evolution of Nanomachines in Geospheres and Microbial Ancestors (ENIGMA) program, an inherent part of the Astrobiology program at NASA, embarked upon a series of extensive laboratory studies. Their findings led them to determine that a simple peptide with two critical nickel atoms served as a "catalyst" of life on Earth billions of years ago. A peptide is a molecule containing two or more amino acids (molecules joining together to form proteins). The specific peptide in question consists of 13 amino acids and binds the two nickel ions.
Scientists using NASA's Kepler telescope have found two distant planets that are in the right place and are the right size for potential life.
© Flickr / Penn State
The team argued that nickel was a metal abundantly present in the early oceans. After binding to the peptide, nickel atoms - as catalysts - pulled other protons and electrons towards themselves, producing hydrogen gas. As for hydrogen, on early planet Earth it was likely a critical source of energy that powered metabolism, the team surmised.
"Scientists believe that sometime between 3.5 and 3.8 billion years ago there was a tipping point, something that kickstarted the change from prebiotic chemistry -- molecules before life -- to living, biological systems. We believe the change was sparked by a few small precursor proteins that performed key steps in an ancient metabolic reaction. And we think we've found one of these 'pioneer peptides,'" Vikas Nanda, a researcher at the Center for Advanced Biotechnology and Medicine (CABM) at Rutgers, said.
Now, thanks to these findings, when researchers scour the universe with telescopes for signs of emerging life, peptides like the one discovered by the Rutgers team could serve as indicative "biosignatures," or, in other words, harbingers of life.
"This work shows that, not only are simple protein metabolic enzymes possible, but that they are very stable and very active -- making them a plausible starting point for life," Vikas Nanda was cited as saying.