Thiosulfate-Hydrogen Peroxide Redox Oscillator as pH Driver for Ribozyme Activity in the RNA World.

Area of Science:

• Origin of Life Studies
• Biochemistry
• Astrobiology

Background:

• The early RNA world, over 3.7 billion years ago, required energy sources for replication and the development of enzymatic functions.
• Thiosulfate-hydrogen peroxide (THP) oscillations are a proposed energy source for early life.
• Ribozymes, RNA molecules with catalytic activity, are central to the RNA world hypothesis.

Purpose of the Study:

• To investigate the impact of THP oscillations on the performance of simple ribozymes.
• To model the coupled evolution of reactants and intermediates under periodic drives.
• To explore the role of dynamic hydrogen peroxide environments in the transition to a cellular world.

Main Methods:

• Experimental rate and thermochemical data were used.
• A dynamical model was developed to simulate self-consistent evolution of reactants and intermediates.
• The responses of two simple ribozymes to periodic pH and thermal drives were examined.

Main Results:

• Ribozyme performance was enhanced by pH cycling.
• Significant performance gains in ribozymes may have required thermal cycling.
• Dynamic hydrogen peroxide environments offer mechanisms for early cellular development.

Conclusions:

• Periodic THP oscillations can power and enhance ribozyme function, supporting the RNA world hypothesis.
• Dynamic chemical environments, like those involving hydrogen peroxide, played a crucial role in the evolution from the RNA world to cellular life.
• Proton gradients, resolving the ribozyme-replication paradox, and vesicle formation are key contributions of dynamic H2O2 media.