Synthetic RNA can make peptides, suggesting the beginnings of life

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Researchers have engineered strands of RNA that can link amino acids together, suggesting a way in which RNA and proteins may have emerged together to form the earliest forms of life.

RNA has long been considered a key molecule in the primordial soup that was Earth a few billion years ago because it can not only store genetic information but also act as an enzyme—two key functions needed for the development of life as we know it. it. But whether RNA-based life really existed, what it looked like, and how it evolved into today’s DNA, RNA, and protein-based organisms remained open questions.

A study published yesterday (May 11) in Nature now points to the possibility that RNAs may have played a role in building early proteins by simply stringing amino acids together. Thomas Carell, an organic chemist at Ludwig Maximilian University in Munich, Germany, and his colleagues created synthetic RNA molecules that could produce peptides as long as 15 amino acids.
Involved in the study. Georgia Tech biophysical chemist Loren Williams, who was also not involved in the research, adds: “If the origins of RNA and the origins of proteins are connected and their origin is not independent, then the math shifts radically in favor of the RNA – protein world and away from the RNA world.”

See “RNA World 2.0”

The researchers engineered RNA molecules to include two modified nucleosides found in ribosomes, enzymes made from RNA, and proteins that synthesize proteins from RNA transcripts. According to Nature , scientists considered these unusual or non-canonical bases to be traces of the components of the ancient primordial broth from which life emerged. The fact that RNAs containing several of these nucleosides were able to bind amino acids and join them together to form peptides “is a very exciting finding,” Martin tells Nature, “not only because it maps a new pathway to an RNA-based peptide.” formation, but because it also reveals new evolutionary significance for naturally occurring modified RNA bases.”

The idea that RNA and peptides may have interacted in the early days of life on Earth provides one way life could have initially evolved without ribosomes. This is useful because ribosomes are complex structures whose origins are largely unclear, Claudia Bonfio, a life chemist at the University of Strasbourg who was not involved in the work, tells Science. “It’s an important advance.”

However, many questions still remain, including when and how ancient RNA molecules may have begun to encode the peptides they help create. Carell tells Nature that it is possible that certain RNAs fold in such a way that they bind specific amino acids in the basic form of genetic coding. Additionally, he adds, if these RNA-peptide hybrid molecules could replicate themselves, they could evolve to become more efficient. “If a molecule can replicate itself, you have something like a mini organism.”