Effect of ‘spent’ nucleotides on nonenzymatic RNA replication

Abstract Nonenzymatic template-directed replication would have been affected by co-solutes in a heterogenous prebiotic soup due to lack of enzymatic machinery. Unlike in contemporary biology, these reactions use chemically-activated nucleotides, which undergo rapid hydrolysis forming nucleoside monophosphates (‘spent’ monomers). These co-solutes cannot extend the primer but continue to base pair with the template, thereby interfering with replication. We therefore aimed to understand how a mixture of ‘spent’ ribonucleotides would affect nonenzymatic replication. We observed inhibition of replication in presence of the mixture, wherein predominant contribution came from the cognate Watson-Crick monomer, showing potential sequence dependence. Our study highlights how nonenzymatic RNA replication would have been directly affected by co-solutes, with ramifications for the emergence of functional polymers in an RNA World.