Poster abstracts
Poster number 173 submitted by Priyanka Priyanka
Prebiotically Plausible Coacervates Support RNA Folding and Ribozyme Catalysis
Priyanka (Department of Chemistry and Biochemistry, University of Notre Dame), Saurja DasGupta (Department of Chemistry and Biochemistry, University of Notre Dame)
Abstract:
Complex coacervates are membraneless, liquidliquid phase-separated compartments that concentrate RNA and other biomolecules, making them useful models for primitive protocells. However, RNA enrichment alone does not ensure RNA function. Coacervates create a distinct chemical environment for encapsulated RNAs by modulating the availability of key cations such as Mg, altering the diffusibility and distribution of reaction components, and introducing molecular crowding. These effects alter RNA folding and become particularly interesting in the context of the functional RNAs such as ribozymes and aptamers. Given the abundance of charged polymers in prebiotic environments, coacervation would have been a certainty; but would coacervate encapsulation provide a fitness benefit to functional RNAs? Here, we examine prebiotically plausible coacervate compositions containing peptides, RNA, and other charged polymers to identify conditions that support both RNA partitioning and function. We show that coacervation increases the ability of RNA to bind small molecules, as evidenced by increased fluorescence of the encapsulated Beetroot aptamer/Thioflavin-T dye system. We demonstrate marked stimulation in the catalytic activities of in vitro evolved ligase ribozymes within coacervates at low concentrations of Mg2+, establishing the beneficial effect of coacervation at low-salt environments. We also show that the coacervate environment provides substantial protection against urea, a prebiotically relevant denaturant of RNA structure. We found that ribozymes are able to function at 2.5 M urea, a concentration high enough to completely inactivate unencapsulated ribozymes in buffer. These findings suggest that certain coacervate environments can support RNA folding and function under conditions that are otherwise unfavourable, thereby advancing early protocell evolution. Our ongoing work focuses on generating more prebiotically plausible coacervates that support RNA function and evolution, with the long-term goal of establishing an ecosystem of cooperating and competing RNA coacervates to simulate early cellular ecologies.
References:
1.B. Drobot, J. M. Iglesias-Artola, K. Le Vay, V. Mayr, M. Kar, M. Kreysing, H. Mutschler and T.-Y. D. Tang, Nat Commun, 2018, 9, 3643.
2.K. K. Le Vay, E. Salibi, B. Ghosh, T. D. Tang and H. Mutschler, eLife, 2023, 12, e83543.
3.T. Walton, S. DasGupta, D. Duzdevich, S. S. Oh and J. W. Szostak, Proc. Natl. Acad. Sci. U.S.A., 2020, 117, 57415748.
4.B. Ghosh, P. M. McCall, K. K. Le Vay, A. Ghosh, L. Hubatsch, D. T. Gonzales, J. Brugus, H. Mutschler and T.-Y. Dora Tang, Nat Commun, 2025, 16, 8765.
Keywords: Coacervates, Ribozyme, Origins of life