Coacervates in a nucleic acid-peptide world – from complex mixtures to functional protocells

Abstract: Mixtures of oppositely charged polypeptides are known to undergo liquid-liquid phase separation, specifically through complex coacervation. Peptide/peptide coacervates support a “peptide-first” hypothesis for the origin of life; however, with the rise of systems chemistry, more heterogeneous scenarios have gained traction. Recent studies suggest that nucleotides and amino acids could have simultaneously formed and polymerized into short, non-coded peptide, DNA, and RNA oligomers. In this talk, I will demonstrate how a systems chemistry approach can help explain the emergence of functional protocells, sharing our recent work on peptide/nucleic acid coacervates. Our findings suggest that even in the early stages of a nucleic acid-peptide world, coacervate droplets likely formed. I will explore how increased compositional complexity—such as heteropolymers, polydisperse mixtures, and mismatched charge concentrations—affects droplet properties like stability and viscosity. Supporting the idea that compositional diversity is crucial for origin-of-life hypotheses, I will show that coacervates composed of mixed short DNA and RNA strands offer advantages over those composed of a single nucleic acid, striking an optimal balance of stability and viscosity to facilitate RNA primer extension.

materials chemistrynanoscienceorganic chemistryphysical chemistrysupramolecular chemistryadaptation and self-organizing systems

Audience: researchers in the topic

( video )

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Systems Chemistry Discussion Series

Series comments: In the past decade, systems chemistry has emerged as a field for studying complex chemical systems akin to life. Systems chemistry is interdisciplinary by nature, with inspirations from various fields including biology, physics and computer science. However, the researchers from different backgrounds tend to lack common "language" to communicate with, as well as common goals to pursue as a field.

In this discussion series, we discuss variety of topics about systems chemistry, such as Brownian ratchet mechanisms, feedback-controlled systems, nonequilibrium thermodynamics, adaptive materials, supramolecular assemblies etc.. We aim at bridging the gaps between the different subfields by free, in-depth discussions on each topic. The discussion is held every 1-2 months. On each occasion, a speaker will give a presentation (20-30 min), followed by discussion (1-1.5 h).

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