A minimal model of stable autocatalytic RNA-replication through integration of replication, molecular regulation, and energy conversion

A minimal model of stable autocatalytic RNA-replication through integration of replication, molecular regulation, and energy conversion

Abstract

Abstract
Catalysis and allostery are complementary principles of biological function: catalysis accelerates biochemical reactions, whereas allosteric regulation dynamically controls molecular interactions. The emergence and persistence of early autocatalytic ribozyme systems likely depended not only on template-directed self-replication but also on ATP production, utilization, and recycling through prebiotically plausible energy-conversion processes. We previously proposed that resistance to molecular parasitism in autocatalytic RNA networks can emerge through hyperparasitic regulation, whereby hyperparasitic ribozymes compete with parasitic ribozymes for binding to the host replicase while additionally binding parasitic ribozymes, thereby redirecting competitive interactions away from host exploitation. Here, we develop a minimal mathematical model of an autocatalytic RNA-world system in which replication, ATP/ADP-based energy conversion, and ATP-dependent allosteric regulation become dynamically coupled. Building on a general reaction framework describing ribozyme replication, catalytic interactions, and ATP/ADP cycling, we identify the minimal regulatory architecture required for stable RNA replication in the presence of parasitic mutants. Our simulations reveal a sequential evolutionary transition in which control precedes optimization. ATP-dependent allosteric regulation first evolves to tame molecular parasitism through hyperparasitic binding, whereby ATP-loaded parasitic ribozymes compete with ATP-free parasites for binding to the host replicase while also binding directly to parasitic ribozymes. This stabilizes RNA replication but simultaneously imposes an energetic cost by sequestering ATP and thereby reducing ATP-ADP turnover. The resulting regulatory burden creates selective pressure for the evolution of ATP synthase/ATPase ribozymes that accelerate ATP-ADP cycling and restore the metabolic flux required for sustained RNA replication. We further identify two plausible evolutionary routes to parasite control: parasitic ribozymes either become intrinsically allostery-prone or are converted into allostery-prone forms by an evolved allosterase ribozyme. Once ATP turnover is sufficiently rapid, both mechanisms confer long-term resistance to recurrent parasitic invasion. These results suggest that stable RNA-based evolution required the progressive integration of information replication, molecular regulation, and increasingly efficient metabolic energy conversion. More generally, the model identifies ATP-dependent allosteric regulation as a plausible evolutionary bridge linking autocatalytic RNA replication to the emergence of regulated proto-metabolism, transforming a parasite-limited replicating system into a self-regulating proto-biological organization capable of sustained evolutionary dynamics.
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