title: Clay catalyzed RNA synthesis under Martian conditions: Application for Mars return samples.
abstract: Catalysis by montmorillonites clay minerals is regarded as a feasible mechanism for the abiotic production and polymerization of key biomolecules on early Earth. We have investigated a montmorillonite-catalyzed reaction of the 5'-phosphorimidazolide of nucleosides as a model to probe prebiotic synthesis of RNA-type oligomers. Here we show that this model is specific for the generation of RNA oligomers despite deoxy-mononucleotides adsorbing equally well onto the montmorillonite catalytic surfaces. Optimum catalytic activity was observed over a range of pH (6-9) and salinity (1 ± 0.2 M NaCl). When the weathering steps of early Earth that generated catalytic montmorillonite were modified to meet Martian soil conditions, the catalytic activity remained intact without altering the surface layer charge. Additionally, the formation of oligomers up to tetramer was detected using as little as 0.1 mg of Na⁺-montmorillonite, suggesting that the catalytic activity of a Martian clay return sample can be investigated with sub-milligram scale samples.
authors.affiliation: The New York Center for Astrobiology, Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY 12180, USA. Electronic address: joship2@rpi.edu.
authors.forename: Prakash C
authors.initials: PC
authors.lastname: Joshi
authors.affiliation: The New York Center for Astrobiology, Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
authors.forename: Krishna
authors.initials: K
authors.lastname: Dubey
authors.affiliation: The New York Center for Astrobiology, Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
authors.forename: Michael F
authors.initials: MF
authors.lastname: Aldersley
authors.affiliation: The New York Center for Astrobiology, Department of Chemistry and Chemical Biology, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
authors.forename: Meaghen
authors.initials: M
authors.lastname: Sausville
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D001546:Bentonite / Q000737:chemistry; D002384:Catalysis; D000077215:Clay; D019418:Evolution, Chemical; D018535:Mars; D009843:Oligoribonucleotides / Q000138:chemical synthesis / Q000737:chemistry; D000069497:Origin of Life; D012313:RNA / Q000138:chemical synthesis* / Q000737:chemistry; D012263:Ribonucleosides / Q000138:chemical synthesis / Q000737:chemistry; D012964:Sodium / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D009843:Oligoribonucleotides; D012263:Ribonucleosides; D001546:Bentonite; D012313:RNA; D012964:Sodium; D000077215:Clay
keywords: Catalysis; Clay minerals; Montmorillonite on Mars; Prebiotic evolution; RNA world