Temperature-Driven Catalytic Switching Enables Sequence-Dependent Amplification of Autocatalytic Ribozymes in...

Area of Science:

• Origin of life studies
• Biochemistry
• Systems chemistry

Background:

• Autocatalytic RNA networks in coacervate droplets are minimal self-reproducing systems.
• Their behavior under fluctuating conditions is not well understood.
• Understanding these dynamics is crucial for origins of life research.

Purpose of the Study:

• Investigate the self-assembly dynamics of Azoarcus ribozyme within coacervates under thermal perturbations.
• Determine the effect of temperature on RNA catalysis and network assembly.
• Explore sequence-specific temperature dependencies and selective amplification.

Main Methods:

• Utilized spermine-polyacrylate coacervates to encapsulate Azoarcus ribozyme.
• Subjected coacervates to controlled thermal perturbations.
• Analyzed ribozyme catalysis, diffusion-limited transport, and reaction kinetics.
• Investigated sequence-specific temperature thresholds and effects of temperature cycling.

Main Results:

• Temperature acts as a switch for ribozyme catalysis, with a specific threshold for autocatalytic RNA assembly.
• Reaction dynamics are arrested below the threshold due to diffusion limitations.
• Switching kinetics and temperature thresholds are sequence-specific for different ribozyme variants.
• Reaction rates inside droplets deviate from Arrhenius behavior, indicating complex catalysis-compartmentalization coupling.
• Temperature cycling leads to differential amplification of ribozyme variants, enabling selective assembly.

Conclusions:

• Fluctuating environments can bias reproduction dynamics in compartmentalized autocatalytic systems.
• Temperature cycling can drive selective amplification and emergence of primitive functional differentiation.
• These findings provide a potential mechanism for early natural selection in protocell models.