RNA and membranes comprise essential features of a prebiotic cell. A genetic polymer able to fold into catalytic structures and replicate itself would naturally benefit from compartmentalization. The role of a membrane in early protocells has most often been discussed in this context, as a passive boundary concentrating genetic reactants and preventing diffusion and dilution of successful RNA replicases. Yet, the coexistence and co-evolution of these two structures suggests a more direct interaction between membranes and RNA should likely have existed. Here, we seek to explore an expanded role for membranes in driving prebiotic RNA replication, from beyond acting as a simple container to localizing RNA oligomers to the membrane surface.  We construct a system that provides temporally controlled,  rapid and robust localization of short RNA oligomers to vesicle membranes. We show how nucleotides modified with both imidazole and lipophilic groups drive RNA association to phospholipid and fatty acid membranes through electrostatic interractions  of RNA with the imidazole groups on membrane-bound nuclotides. We show this localization occurs through both  FRET and microscopy methods and explore the role of the nucleotide base, membrane composition, and the presence of divalent cations on oligomer localization. The current system provides a tool for understanding the cooperative interactions between biophysical membrane processes and chemical RNA replication when both structures are directly associated.

Driving RNA to protocell membranes

248th National Meeting (2014)

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