Researchers from the University of Granada have "resurrected" a 4-billion-year-old fossil protein that sheds light on how life on Earth may have evolved.
Researchers from the University of Granada "resurrected" a 4-billion-year-old fossil protein named thioredoxins, which they believe probably existed in the most primitive life forms.
"So far, attempts to understand protein structure evolution have been based on the comparison between structures of modern proteins. This is equivalent to trying to understand the evolution of birds by comparing several living birds," senior study author Jose Sanchez-Ruiz of the University of Granada, said in a statement.
Fossils are the best resources to understand life evolution. Hence, researchers decided to recreate fossil proteins in labs to understand their features. For this study, researchers chose thioredoxin as the protein is found in most organisms from the three domains of life: bacteria, archaea and eukaryotes.
Previously, researchers recreated the protein precambrian and discovered that it resembled proteins that existed when life first evolved. This led researchers to conclude that protein structures remain constant over extended periods of time.
"The putative ancestral structures reported here are consistent with the thioredoxin fold being an approximate 4 billion-year-old molecular fossil of sorts and confirms that protein structures can evolve slowly," Sanchez-Ruiz and his colleagues wrote in the study.
Researchers also found that the protein was highly stable and was able to bind with different chemicals and function in acidic environments too.
Sanchez-Ruiz told LiveScience that this finding makes a lot of sense as it is believed the temperatures were very high and oceans extremely acidic four billion years ago.
"We have looked at a number of gene families now, and for all of them we find the most ancient proteins are the most thermally stable. From this, we conclude that ancient life lived in a hot environment," Eric Gaucher, a professor at Georgia Tech who helped with the study, told the BBC after testing the protein to see how well it coped with heat.
Since the proteins are recreations made in the lab, scientists cannot confirm how similar the replicas are to the original. However, they confirmed that the properties were consistent with proteins that may have existed four billion years ago.
Another interesting discovery made in the study was that the protein may have existed in another planet, probably Mars.
"Four billion years ago, Mars was a much a safer place than Earth. Maybe we have resurrected Martian proteins. Maybe the last universal common ancestor (the first life) formed on Mars and transferred to Earth," Sanchez-Ruiz told the BBC.
