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RNA world accelerated by dissolved iron (II)?

RNA world accelerated by dissolved iron (II)?. Group A22: Joseph Bryant, Yoon Jung Choi, Hsiang Hsu, Anthony Tsou, Emily Moyer. Introduction. Life originated with RNA-based genetic and metabolic systems (RNA world) RNA replaced by proteins after creation of oxygen

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RNA world accelerated by dissolved iron (II)?

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  1. RNA world accelerated by dissolved iron (II)? Group A22: Joseph Bryant, Yoon Jung Choi, Hsiang Hsu, Anthony Tsou, Emily Moyer

  2. Introduction • Life originated with RNA-based genetic and metabolic systems (RNA world) • RNA replaced by proteins after creation of oxygen • Currently, RNA uses magnesium ions (Mg2+) as catalysts • Fe2+ could be a mimic of Mg2+ in the absence of O2 • Iron was abundant in the Archaean time while oxygen was not • It is suggested that iron ions (Fe2+) could have been used for RNA prior to the Great Oxygenation Event http://www.uic.edu/classes/phys/phys461/phys450/ANJUM04/ (HIERARCHY AND DYNAMICS OF RNA FOLDING, 2012)

  3. Experiment 1 Results and Data • Prediction: RNA conformation is conserved if Fe2+ substitutes for site-bound Mg2+ • The Density Functional Theory (DFT) shows that the RNA-Mg2+ clamp and an RNA-Fe2+ clamp are nearly identical http://www.plosone.org/article/fetchObject.action?uri=info:doi/10.1371/journal.pone.0038024.g001&representation=PNG_M (RNA Folding and Catalysis Mediated by Iron (II), 2012)

  4. Experiment 1 Results and data Continued http://www.plosone.org/article/fetchObject.action?uri=info:doi/10.1371/journal.pone.0038024.g002&representation=PNG_M • Chemical footprinting: • SHAPE used accurately predict and confirm secondary structures of RNA • Pattern of SHAPE reactivity for the specific domain of RNA observed is conserved when Mg2+ is replaced by Fe2+ under anaerobic conditions (RNA Folding and Catalysis Mediated by Iron (II), 2012)

  5. Experiments 2 and 3 Results and Data L1 ribozyme ligase: • Catalytic activity of ribozyme tested in presence of Mg2+ or Fe2+,in absence of oxygen • Initial rate of ligation: • 100 µM Mg2+ = 1.4 × 10-6min-1 • 100 µM Fe2+ = 3.5 × 10-5 min-1 • 25 times larger in Fe2+ Hammerhead ribozyme: • Initial rate of cleavage: • 25 µM Mg2+ = 0.011 min-1 • 25 µM Fe2+ = 0.035 min-1 • 3 times larger in Fe2+ (RNA Folding and Catalysis Mediated by Iron (II), 2012) http://www.plosone.org/article/fetchObject.action?uri=info:doi/10.1371/journal.pone.0038024.g003&representation=PNG_M

  6. Discussion • Greater abundance of Fe2+ than Mg2+ • RNA with Fe2+ supports more diverse RNA structure and catalytic functions than RNA with Mg2+ • Conversion of one metal to another is facile in some protein enzymes • RNA fragment that forms multiple first-shell interactions with Mg2+ doesn’t change with Fe2+substitution • Fe2+ substitute for Mg2+ to support catalysis by ribozymes (On the Origin of the Special Role of Magnesium in RNA Folding, 2010) (Dissolved Iron May Have Been Key to RNA-based Life, 2012) (On the Role of Magnesium Ions in RNA Stability, 2000)

  7. Conclusion • In response to the criticisms against the RNA world hypothesis, the RNA functions very readily and efficiently when Fe2+ is incorporated, which makes RNA molecules possible originations of all lives. http://upload.wikimedia.org/wikipedia/commons/2/28/Full_length_hammerhead_ribozyme.png

  8. Literature Cited Misra, Vinod K., and David E. Draper. "On the Role of Magnesium Ions in RNA Stability."Bipolymers. Vol. 48. N.p.: n.p., 2000. N. pag. Print. Athavale, Shreyas S., Anton S. Petrov, Chiaolong Hsiao, Derrick Watkins, Caitlin D. Prickett, J. Jared Gossett, Lively Lie, Jessica C. Bowman, Eric O'Neill, Chad R. Bernier, Nicholas V. Hud, Roger M. Wartell, Stephen C. Harvey, and Loren Dean Williams. "RNA Folding and Catalysis Mediated by Iron (II)." RNA Folding and Catalysis Mediated by Iron (II) (2012): n. pag. PLOS ONE:. Web. 26 Oct. 2012. <http://www.plosone.org/article/info:doi/10.1371/journal.pone.0038024>. Thompson, Helen. "Nature.com." Dissolved Iron May Have Been Key to RNA-based Life : Nature News Blog. Nature Publishing Group, 01 June 2012. Web. 26 Oct. 2012. <http://blogs.nature.com/news/2012/06/dissolved-iron-may-have-been-key-to-rna- based-life.html>. Brion, Philippe, and Eric Westhof. "HIERARCHY AND DYNAMICS OF RNA FOLDING." Biophysics 26 (1997): 113-37. Annual Reviews: A Nonprofit Scientific Publisher. Web. 26 Oct. 2012. <http://www.annualreviews.org/doi/abs/10.1146/ annurev.biophys.26.1.113>. Petrov, Anton S., Jessica C. Bowman, Stephen C. Harvey, and Loren Dean Williams. "Bidentate RNAâ-magnesium Clamps: On the Origin of the Special Role of Magnesium in RNA Folding." RNA: A Publication of the RNA Society. N.p., 10 Dec. 2010. Web. 26 Oct. 2012. <http://rnajournal.cshlp.org/content/17/2/291.short>

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