A small prehistoric molecule from Earth could pave the way to find life in the cosmos.
A team of scientists from Rutgers University in New Jersey (USA) has discovered the origins of the protein structures responsible for metabolism, the building blocks of life : simple molecules that powered early life on Earth and serve as chemical signals that NASA could use to search for life on other planets in the future. The study has been published in the journal Proceedings of the National Academy of Sciences.
Researchers from the ENIGMA team (Evolution of Nanomachines in Geospheres and Microbial Ancestors) have detailed the evolution of proteins since 3.5 billion years ago.
” We believe we have found the building blocks of life – the Lego set that ultimately led to the evolution of cells, animals and plants,” study lead author Paul G. Falkowski said in a statement. , Principal Investigator for ENIGMA.
Proteins of metabolism?
Metabolic proteins are essentially chains of amino acids that convert nutrients into energy in any living organism. As if they were small machines. These proteins “are what digest food, act as chemical signals in our body, transport hemoglobin, transport oxygen through our body,” explains Hagai Raanan, leader of the work.
To understand the origin of life on Earth, the researchers reconstructed, as if they were forensic doctors, what proteins looked like almost 4 billion years ago, a highly complicated feat given that there are no fossils from that time and, therefore hence organic molecules, from that moment on.
Thus, as if it were a puzzle of thousands of pieces, they reconstructed the evolution of enzymes (proteins) from the present to the deep past over the course of 10 million years. The solution to the puzzle required two missing pieces, and life on Earth could not exist without them. By building a network connected by their roles in metabolism, the scientists discovered the missing pieces: ferredoxin, which binds iron and sulfur compounds and shifts electrons so metabolism can take place, and the Rossmann fold, which is involved. in the production of DNA.
Both folds appear to have ancient ancestors, the study suggests. And, if the findings are true, they may be the root of metabolism, the essential process for life, and a possible signature of life on other worlds.
“We believe that life was built from very small building blocks and emerged as a Lego set to make more complex cells and organisms like us,” explained Paul G. Falkowski, principal investigator at ENIGMA. “We believe we have found the building blocks of life – the Lego set that ultimately led to the evolution of cells, animals and plants.”
Referencia: Hagai Raanan el al., “Small protein folds at the root of an ancient metabolic network,” PNAS (2020). www.pnas.org/cgi/doi/10.1073/pnas.1914982117
