Poster abstracts
Poster number 88 submitted by McCauley Meyer
Nucleotide level resolution of RNA folding interactions within peptide-based complex coacervates
McCauley O. Meyer (Biochemistry, Microbiology, and Molecular Biology, Penn State University), Saehyun Choi (Chemistry, Penn State University), Fatma P. Cakmak (Chemistry, Penn State University), Christine D. Keating (Chemistry, Penn State University), Philip C. Bevilacqua (Biochemistry, Microbiology and Molecular Biology, Chemistry, Penn State University)
Abstract:
Understanding how life arose is one of the great questions facing humanity. The RNA World Hypothesis partially addresses this by providing a genetic component as well as an enzymatic one, but does not provide for how RNA-compatible cells arose. A potential RNA-compatible protocell model that has recently garnered attention is complex coacervates. Coacervates are molecule-rich droplets formed via liquid-liquid phase separations (LLPS) primarily by electrostatic interaction of poly-cationic and poly-anionic polymers leading to a reduced water content inside of the droplets. Coacervates have been demonstrated to form with both biotic and abiotic polymers and have also been shown to strongly partition nucleic acids, amino acids and metal ions. As protocells, they have been mostly studied from a physical/chemical point of view; however, there has been little characterization of them with regard to whether RNA catalysis and replication could occur within them.
Herein I describe our early efforts toward characterizing RNA folding interactions at the nucleotide level within complex coacervates made from lysine homo-polymers and aspartic acid homo-polymers, as well as lysine homo-polymers and ATP. Nucleotide-level resolution of the folding status of the model RNA, tRNAphe from S. cerevisiae, was assessed by in-line probing. Through this method, a variety of additional coacervates made from both lysine and aspartic acid homo-polymers of different lengths were also investigated. Some coacervates promoted native folding of the tRNA, while others led to strand-specific denaturation. The effects on folding also differed based on polymer length and identity. These studies serve as a proof-of-concept that nucleotide-level resolution of RNA folding states within complex coacervates can be obtained and that this technique should be applicable to other functional RNAs including ribozymes.
Keywords: Liquid-Liquid Phase Separation, RNA folding, Early Earth