Endurance Strategies: Building Blocks of Life Amidst Early Earth’s Intense Radiation
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The emergence of life on Earth is shrouded in mysteries, and one of the perplexing puzzles is how the essential molecules for life withstand the intense radiation prevalent during the early stages. While space harbors intricate chemistry, including amino acids found in asteroids, radiation poses a significant threat to delicate molecular structures. A recent study led by Professor Bing Tian from Zhejiang University explores a potential safeguard against radiation—manganese ions.
The Menace of Radiation and the Resilience of Deinococcus radiodurans
The early Earth was subjected to substantial gamma radiation, a formidable challenge for organic molecules. Deinococcus radiodurans, a bacterium renowned for surviving lethal radiation doses, offers insights into how early life forms might have coped with such hostile conditions.
Previous studies revealed the bacterium’s reliance on manganese 3+ ions to shield vulnerable molecules from radiation-induced oxidative stress.
Polyphosphates and Manganese: A Dynamic Duo in Radiation Defense
The researchers hypothesized that phosphate residues, specifically polyphosphates, might collaborate with manganese ions in offering protection. Polyphosphates, present on Earth long before the emergence of life, were known to contribute phosphates to crucial molecules like ATP.
The team constructed model protocells from coacervates liquid droplets to test their theory and exposed them to substantial gamma radiation.
Manganese-Powered Resilience: A Key Revelation
The results were striking. Coacervates containing polyphosphate-manganese emerged unscathed, even preserving proteins from the surrounding environment. In contrast, coacervates with polyphosphates paired with a peptide instead of manganese were annihilated.
Manganese ions, acting as antioxidants, proved highly effective in scavenging reactive oxygen species, leaving proteins undamaged. The experiment, repeated with DNA, showcased similar radiation resistance.
Bridging the Gap: From Protocells to the Origin of Life
While the study marks a significant stride in understanding how life’s precursors may have overcome radiation challenges, it acknowledges the complexity involved in the transition from manganese ions and polyphosphates to the intricate process of self-replication.
Nevertheless, this research addresses a previously insurmountable obstacle to unraveling the mysteries of life arising from non-life.
Read the original article on Nature Communications.
Read more: Ideal Stars for Finding Life.
