Interactions of mononucleotides with prebiotically pertinent protocellular membranes

Abstract

Lipids and nucleotides are two major classes of biomolecules in both the prebiotic world and contemporary biology, which are central to compartmentalisation and information transfer, respectively. The emergence of life on Earth would have fundamentally been affected by the spontaneous interactions between nucleotides and lipid membranes. However, the effects of nucleotides on prebiotically relevant protocellular membranes remains poorly understood. To this end, we investigated the effect of the disodiated salts of canonical nucleotides on the physicochemical properties of fatty acid membranes. We did this in both buffered and prebiotically relevant analogue conditions, wherein we used hot spring water samples from astrobiologically relevant sites in Ladakh, India. The characteristics of nucleobases (of the nucleotides), the lipid headgroups, and the ionic makeup of the suspensions, were all found to influence nucleotide-membrane interactions, in turn influencing membrane properties. The effect of nucleotides was also checked on the formation and stability of the vesicles under prebiotically relevant analogue conditions. All the nucleotides except guanosine 5’-monophosphate were found to facilitate vesicle formation in otherwise destabilising conditions of terrestrial geothermal pool and lower pH regimes. Our results showcase the importance of nucleotide-membrane interactions in the emergence of protocells on the early Earth. Previous studies have shown tangible benefits of the presence of lipids on processes and properties of nucleotides, including their oligomerisation and stability. In here, we offer an example of a prebiotically plausible reciprocal relationship between lipids and nucleotides, where their coexistence would have been mutually beneficial to each other.