Title:
A Liquid Crystal Autocatalysis for the origin of the first nucleic acids

Abstract:
Based on a broad experimental exploration of the collective behavior of short DNA and RNA oligomer1 (oligoNA) and mononucleotides2, I will report recent progresses in the investigation of a pathway, which we named Liquid Crystal Autocatalysis, by which linear self-assembly and spontaneous Liquid Crystal (LC) ordering might have enhanced the prebiotic formation of long and potentially active RNA polymers. The key features of this autocatalytic pathway are a hierarchy of base pairing and stacking, linear aggregation, phase separation of sequences and structures, and LC ordering, which can select oligoNA or monomers, and template their polymerization3,4 inside compact, ordered yet fluid micro-domains. According to this scenario, during drying-wetting cycles LCs continuously form and melt, depending on temperature, concentration and length of the constituent molecules. Herein the supramolecular assembly acts as a template guiding intermolecular ligation toward the formation of long lin
ear chains which in turn stabilize the whole self-assembly, establishing a self-sustained positive feedback loop.

References:
[1] Fraccia TP et al. (2016) Liquid Crystal Ordering and Isotropic Gelation in Solutions of 4-base-long DNA Oligomers. ACS Nano 10:8508.
[2] Smith GP, Fraccia TP et al. (2018) Backbone-free duplex-stacked monomer nucleic acids exhibiting Watson-Crick selectivity. PNAS In press.
[3] Fraccia TP et al. (2015) Abiotic Ligation of DNA Oligomers Templated by their Liquid Crystal Ordering. Nat. Commun. 6:6424.
[4] Todisco M, Fraccia TP et al. (2018) Non-enzymatic polymerization into long linear RNA catalyzed by liquid crystal self-assembly. ACS Nano under review