Transient and sustained elementary flux mode networks on a catalytic string-based chemical evolution model

Area of Science:

• Biochemistry
• Origin of Life Research
• Theoretical Chemistry

Background:

• Theoretical models for prebiotic evolution often lack direct links between model components and real-world chemistry.
• The metabolism-first hypothesis suggests metabolic networks preceded genetic systems in early life.

Purpose of the Study:

• To develop a more interpretable theoretical model for prebiotic evolution.
• To investigate the emergence of metabolic network features from fundamental chemical principles.

Main Methods:

• Developed the string-based model SSE (steady state evolution) using carbon compound chemistry principles.
• Focused on energetics and used equilibrium constants to track energy flow.
• Employed elementary flux mode (EFM) analysis to detect metabolic networks.

Main Results:

• The SSE model successfully generated metabolic and catalytic networks with features like stepwise synthesis, energy coupling, and catalytic cascades.
• Observed phenomena included redox coupling, intermediate cycling, and autocatalytic cycles.
• Results indicated these metabolic features arise from catalytic system principles, independent of genetic systems.

Conclusions:

• The study provides strong theoretical support for the metabolism-first hypothesis.
• Key features of biological metabolism are likely a consequence of evolutionary processes in open systems with a food source.
• Catalytic system principles are fundamental to understanding the origin of metabolism.