RNA is thought to have played a key role in life getting started
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Researchers have made significant progress towards understanding how life originated by developing a system of RNA molecules capable of partial self-replication. This breakthrough brings us closer to achieving complete self-replication for the first time.
RNA, a vital molecule in the origins of life, has the unique ability to store information like DNA and catalyze reactions like proteins. While not as efficient as DNA or proteins individually, RNA’s dual functionality has led many scientists to believe that life may have begun with self-replicating RNA molecules. According to James Attwater from University College London, RNA was the molecule that governed biology.
Despite its importance, creating self-replicating RNA molecules has posed challenges due to the strong tendency of RNA double helices to rejoin, hindering the replication process. However, researchers led by Attwater have discovered that sets of three RNA letters, known as triplets, can effectively prevent the reformation of double helices. By utilizing triplets, the team has developed a system where an RNA enzyme in double-helix form is combined with these triplets.
The process involves making the solution acidic and heating it to 80°C to separate the helix, allowing the triplets to pair up and form the structure. Subsequently, the solution is alkalinized and cooled to -7°C, causing the water to freeze and concentrate the liquid, activating the RNA enzyme to join the triplets and create a new strand.
While the current replication process is limited to 30 letters of the 180-letter RNA enzyme, researchers are optimistic about achieving complete replication by enhancing the enzyme’s efficiency.
Attwater highlights the intriguing properties of this simple molecule system, suggesting a potential link between triplet RNA letters and the triplet code used in specifying protein sequences in modern cells. The team’s findings also indicate that the triplets most likely involved in natural replication bind strongly, hinting at a connection to the earliest genetic code.
The researchers believe that the natural conditions required for this replication process could have existed on Earth, particularly in geothermal systems like Icelandic hot springs with varying pH levels. Zachary Adam from the University of Wisconsin-Madison notes the significance of RNA nucleotide triplets in cellular translation and finds the study intriguing for exploring a non-informatic role of RNA prior to the emergence of living cells.
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