Ribonucleic acid (RNA) is a fundamental biological molecule that plays a crucial role in the genetics of organisms and the evolution of life. It shares similarities with DNA but has unique functions and properties that make it essential for life processes. A recent study published in the journal Proceedings of the National Academy of Sciences sheds light on the process of RNA folding at low temperatures and its potential implications for primordial biochemistry and the evolution of life on Earth.
RNA is composed of ribose molecules linked with phosphate groups and nitrogenous bases (adenine, guanine, cytosine, uracil). The sequence of bases and the spatial conformation of RNA are key determinants of its biological functions. The study focuses on understanding the diverse structures that RNA assumes when it folds in on itself, which are essential for its biological activity.
The research team led by Professor Félix Ritort discovered that RNA sequences forming hairpin structures adopt new compact configurations below 20°C. This temperature range between +20°C and -50°C reveals unexpected novel structures in RNA molecules. The stability of RNA reaches its peak at +5°C due to ribose-water interactions, but below this temperature, the RNA unfolds again, leading to cold denaturation. The study suggests that this unique phenomenon is common to all RNA molecules but can be influenced by sequence, salt, and acidity.
The findings have significant implications for the biochemistry and biological functions of RNA. The dominance of ribose-water interactions challenges the traditional rules of RNA stabilization based on A-U and G-C pairing. This altered biochemistry has potential implications for organisms inhabiting cold environments, such as psychrophiles in alpine regions and deep ocean waters. The study introduces the concept of a “sweet-RNA world,” a primitive biochemistry based on ribose and sugars that predates the evolution of RNA itself. This could have originated in cold environments in outer space, influenced by thermal cycles and celestial bodies.
The study on RNA folding at low temperatures offers new insights into the primordial biochemistry and evolutionary history of life on Earth. The discovery of novel structures in RNA molecules and the impact of ribose-water interactions challenge the conventional understanding of RNA stability. The concept of a “sweet-RNA world” suggests a primitive form of biochemistry that could have evolved in cold environments in outer space. Further research in this area could provide valuable information on the origins of life and the role of RNA in the evolution of living organisms.
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