Abstract
One of the mysteries in studying the molecular “Origin of Life” is the emergence of RNA and
RNA-based life forms, where non-enzymatic polymerization of nucleotides is a crucial hypothesis
in formation of large RNA chains. The non-enzymatic polymerization can be mediated by various
environmental settings such as cycles of hydration and dehydration, temperature variations and
proximity to a variety of organizing matrices such as clay, salt, fatty acids, lipid membrane and
mineral surface. In this work, we explore the influence of different phases of the lipid membrane
towards nucleotide organization and polymerization in a simulated prebiotic setting. We calculate
the free energy cost of localizing a mononucleotide, Uridine monophosphate (UMP), in distinct
membrane settings and we perform all-atom molecular dynamics (MD) simulations to estimate
the role of the monophasic and biphasic membrane in modifying the behavior of UMPs localization
and their clustering mechanism. Based on the free-energy and diffusion data from our MD
calculations, we develop a lattice based model to explore the thermodynamic limits of the observations
made from the MD simulations. The mathematical model substantiates our hypothesis that
the lipid layers can act as unique substrates for ‘catalyzing’ polymerization of mononucleotides
due to the inherent spatiotemporal heterogeneity and phase change behavior.
