title: RNA Oligomerization in Laboratory Analogues of Alkaline Hydrothermal Vent Systems.
abstract: Discovering pathways leading to long-chain RNA formation under feasible prebiotic conditions is an essential step toward demonstrating the viability of the RNA World hypothesis. Intensive research efforts have provided evidence of RNA oligomerization by using circular ribonucleotides, imidazole-activated ribonucleotides with montmorillonite catalyst, and ribonucleotides in the presence of lipids. Additionally, mineral surfaces such as borates, apatite, and calcite have been shown to catalyze the formation of small organic compounds from inorganic precursors (Cleaves, 2008 ), pointing to possible geological sites for the origins of life. Indeed, the catalytic properties of these particular minerals provide compelling evidence for alkaline hydrothermal vents as a potential site for the origins of life since, at these vents, large metal-rich chimney structures can form that have been shown to be energetically favorable to diverse forms of life. Here, we test the ability of iron- and sulfur-rich chimneys to support RNA oligomerization reactions using imidazole-activated and non-activated ribonucleotides. The chimneys were synthesized in the laboratory in aqueous "ocean" solutions under conditions consistent with current understanding of early Earth. Effects of elemental composition, pH, inclusion of catalytic montmorillonite clay, doping of chimneys with small organic compounds, and in situ ribonucleotide activation on RNA polymerization were investigated. These experiments, under certain conditions, showed successful dimerization by using unmodified ribonucleotides, with the generation of RNA oligomers up to 4 units in length when imidazole-activated ribonucleotides were used instead. Elemental analysis of the chimney precipitates and the reaction solutions showed that most of the metal cations that were determined were preferentially partitioned into the chimneys.
authors.affiliation: 1 New York Center for Astrobiology, Rensselaer Polytechnic Institute , Troy, New York.|2 Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute , Troy, New York.
authors.forename: Bradley T
authors.initials: BT
authors.lastname: Burcar
authors.affiliation: 3 NASA Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California.|4 NASA Astrobiology Institute , Icy Worlds.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Barge
authors.affiliation: 1 New York Center for Astrobiology, Rensselaer Polytechnic Institute , Troy, New York.|5 Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute School of Science , Troy, New York.
authors.forename: Dustin
authors.initials: D
authors.lastname: Trail
authors.affiliation: 1 New York Center for Astrobiology, Rensselaer Polytechnic Institute , Troy, New York.|5 Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute School of Science , Troy, New York.
authors.forename: E Bruce
authors.initials: EB
authors.lastname: Watson
authors.affiliation: 3 NASA Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California.|4 NASA Astrobiology Institute , Icy Worlds.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Russell
authors.affiliation: 1 New York Center for Astrobiology, Rensselaer Polytechnic Institute , Troy, New York.|2 Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute , Troy, New York.
authors.forename: Linda B
authors.initials: LB
authors.lastname: McGown
mesh_terms: D000249:Adenosine Monophosphate / Q000737:chemistry; D001546:Bentonite / Q000737:chemistry; D002384:Catalysis; D019281:Dimerization; D019418:Evolution, Chemical; D006157:Guanosine Monophosphate / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D060086:Hydrothermal Vents / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry; D007501:Iron / Q000737:chemistry*; D009792:Oceans and Seas; D009843:Oligoribonucleotides / Q000138:chemical synthesis*; D000069497:Origin of Life; D012313:RNA / Q000138:chemical synthesis*; D012265:Ribonucleotides / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry*; D014542:Uridine Monophosphate / Q000737:chemistry
chemical_list: D007093:Imidazoles; D009843:Oligoribonucleotides; D012265:Ribonucleotides; D001546:Bentonite; D000249:Adenosine Monophosphate; D012313:RNA; D013455:Sulfur; D006157:Guanosine Monophosphate; D007501:Iron; D014542:Uridine Monophosphate