Researchers have made significant progress in unraveling one of biology’s most profound puzzles: how the fundamental molecules of life came together over 4 billion years ago.
Proteins, composed of chains of amino acids, are pivotal to life, supporting tissue structure and performing countless functions within an organism. However, they lack the ability to self-replicate.
This task falls to RNAs, which serve as messengers and translators of genetic information in all living cells today.
The enigma lies in how these two distinct types of molecules first interacted, ultimately leading to the genetic code and the chain of events that produced us.
“RNA molecules transmit information between themselves in a highly predictable and efficient manner, but they struggle to communicate with the amino acids required for protein synthesis,” explains Senior Author of the study, Professor Matthew Powner told BBC Science Focus.
“For decades, the mechanisms and reasons behind the initial linkage of these two molecules have remained open questions.”
Previous laboratory attempts to replicate this chemistry faced challenges, as amino acids typically reacted with one another rather than with RNA, and unstable states in water hindered the reactions.
Adopting an innovative approach, the Powner team combined amino acids into a sulfur-containing compound called thioesters, a high-energy bond still utilized by cells today. This allowed for natural and selective reactions between the molecules and RNA.
Intriguingly, the inherent structure of RNA appears to direct amino acids to the proper position at the RNA strand’s edge.
This suggests a viable chemical pathway through which fundamental processes in life began, without the necessity of more complex catalysts like enzymes.
“All these molecules were quite simple and likely present on the early Earth,” Powner noted.
The early ocean’s conditions would have been too limiting for these reactions to proceed, but nutrient-laden pools, ponds, and lakes offered an ideal environment.
This research also connects two longstanding theories: the “RNA world,” which emphasizes RNA’s crucial role, and the “thioester world,” which suggests high-energy thioesters were vital for early metabolism.
For Powner, the upcoming challenge is clear: he aims to “understand the origins of the universal genetic code of life.” This understanding could lead to insights on exactly how and where it originated on our planet.
“Scientists are constructing a validated framework that could lead to the creation of ‘cells’,’” Powner adds.
These cells not only have the potential to evolve but also to illuminate the origins of universal life structures and their organization.
“These reactions provide the crucial information needed to reasonably explore how and where life began on Earth.”
read more:
About our experts
Matthew Powner is a professor of organic chemistry at the University of London. His work focuses on the chemistry related to life’s origins, and alongside his research group, he contributes to fields such as nucleic acid and amino oxidation, protometabolic networks, ribozymes, lipids, crystal engineering, green chemistry, catalysis, and photochemistry.
Source: www.sciencefocus.com
