Thermally Accessible Prebiotic Pathways for Forming Ribonucleic Acid and Protein Precursors from Aqueous Hydrogen Cyanide

The
search for prebiotic chemical pathways to biologically relevant
molecules is a long-standing puzzle that has generated a menagerie
of competing hypotheses with limited experimental prospects for falsification.
However, the advent of computational network exploration methodologies
has created the opportunity to compare the kinetic plausibility of
various channels and even propose new pathways. Here, the space of
organic molecules that can be formed within four polar or pericyclic
reactions from water and hydrogen cyanide (HCN), two established prebiotic
candidates for generating biological precursors, was comprehensively
explored with a state-of-the-art exploration algorithm. A surprisingly
diverse reactivity landscape was revealed within just a few steps
of these simple molecules. Reaction pathways to several biologically
relevant molecules were discovered involving lower activation energies
and fewer reaction steps compared with recently proposed alternatives.
Accounting for water-catalyzed reactions qualitatively affects the
interpretation of the network kinetics. The case-study also highlights
omissions of simpler and lower barrier reaction pathways to certain
products by other algorithms that qualitatively affect the interpretation
of HCN reactivity.