Non‐Enzymatic RNA Backbone Proofreading through Energy‐Dissipative Recycling

Non‐enzymatic oligomerization of activated ribonucleotides leads to ribonucleic acids that contain a mixture of 2′,5′‐ and 3′,5′‐linkages, and overcoming this backbone heterogeneity has long been considered a major limitation to the prebiotic emergence of RNA. Herein, we demonstrate non‐enzymatic chemistry that progressively converts 2′,5′‐linkages into 3′,5′‐linkages through iterative degradation and repair. The energetic costs of this proofreading are met by the hydrolytic turnover of a phosphate activating agent and an acylating agent. With multiple rounds of this energy‐dissipative recycling, we show that all‐3′,5′‐linked duplex RNA can emerge from a backbone heterogeneous mixture, thereby delineating a route that could have driven RNA evolution on the early earth.