Non-Watson-Crick RNA synthesis suited to origin functions

Area of Science:

• Biochemistry
• Origin of Life Studies
• RNA Synthesis

Background:

• RNA plays a central role in genetic information storage and transfer.
• Understanding the prebiotic synthesis of RNA components is crucial for understanding the origin of life.
• Templated synthesis offers a potential pathway for the non-enzymatic formation of RNA precursors.

Purpose of the Study:

• To investigate the templated synthesis of adenosine triphosphate (AppA) using guanosine tetraphosphate (GppG) as a template.
• To characterize the kinetics and conditions of this novel templated reaction.
• To explore the implications of this pathway for early genetic systems and the origin of encoded functions.

Main Methods:

• Characterization of RNA synthesis reactions involving adenosine monophosphate (pA) and inosine monophosphate (ImpA) precursors.
• Kinetic analysis of AppA formation in the presence and absence of various nucleotide templates, including GppG.
• Investigation of reaction order, salt concentrations, and pH sensitivity.

Main Results:

• GppG significantly accelerates the synthesis of AppA from pA and activated ImpA precursors.
• This templated synthesis follows third-order kinetics (first order in pA, ImpA, and GppG).
• The reaction is less sensitive to temperature and pH compared to other templated RNA synthesis methods.

Conclusions:

• GppG acts as a template for AppA synthesis via G:A base-pairing, a process termed para-templating.
• Para-templating represents a simpler molecular route to encoded chemical functions, potentially preceding more complex genetic systems.
• This pathway may have arisen from localized nucleobase synthesis events and served as an evolutionary precursor to modern genetic expression.