Fig. 8. For self-replicating systems to function inside coacervate protocells, each step of the replication process has to remain functional: selective template recognition by the building blocks, ligation/polymerization and template duplex dissociation. Additionally, coacervates can give selective enrichment of certain replicator sequences. (a) Template recognition between building blocks and the template. Iglesias-Artola et al. showed by Fluorescence Recovery After Photobleaching (FRAP) that the R3C ligase replicator template and building block have similar diffusion coefficients in coacervates made from K9 and the replicator RNA. Adapted from ref. 100. (b) Efficient ligation/polymerization. Fraccia and Martin observed efficient ligation of dsDNA inside both liquid crystalline and isotropic coacervate droplets. Adapted from ref. 94. (c) Dissociation of the template duplex to release the copied template. Nott et al. observed melting of 12-mer DNA duplexes inside Ddx4 coacervates using Förster Resonance Energy Transfer (FRET). Adapted with permission from ref. 98. Copyright (2016) Springer Nature Limited. (d) Selective enrichment of replicator sequences inside coacervates. Lu et al. showed that in coacervates of polylysine with different nucleoside triphosphates (NTPs), polynucleic acid sequences that can form Watson–Crick–Franklin base pairs with the NTP are selectively enriched, while partitioning is less selective in coacervates made with all four NTPs. Adapted from ref. 101.
