Reflections on the Origin of Coded Protein Biosynthesis

Area of Science:

• Biochemistry
• Origin of Life Studies
• Molecular Evolution

Background:

• The emergence of life involved the development of complex biochemical pathways.
• Protein synthesis is a fundamental process, crucial for life's origins.
• Key catalysts in protein synthesis include DNA-dependent RNA polymerases, aminoacyl-tRNA synthetases, and ribosomes.

Purpose of the Study:

• To investigate the catalytic mechanisms of primordial biocatalysts.
• To explore the principle of continuity in the evolution of biological systems.
• To understand the role of substrate-assisted catalysis in early life.

Main Methods:

• Analysis of structural and functional studies of key biocatalysts.
• Examination of the chemical properties of nucleotidic components.
• Investigation of substrate binding modes and their impact on reaction kinetics.

Main Results:

• Primordial biocatalysts lack chemically active groups, relying on substrate-assisted catalysis.
• Substrates form an 'entropy trap,' lowering activation entropy and excluding water.
• Reactions catalyzed by these mechanisms are simpler than modern enzymatic reactions.

Conclusions:

• Substrate-assisted catalysis and entropy trapping explain the efficiency of early biocatalysts.
• The complementary reactivity of β-d-ribose and phosphate likely led to their selection for early coding polymers.
• These findings support the principle of continuity in the evolution of biological catalysis.