Meteorite-catalyzed syntheses of nucleosides and of other prebiotic compounds from formamide under proton irradiation

Proc Natl Acad Sci U S A. 2015 May 26;112(21):E2746-55. doi: 10.1073/pnas.1422225112. Epub 2015 Apr 13.

Abstract

Liquid formamide has been irradiated by high-energy proton beams in the presence of powdered meteorites, and the products of the catalyzed resulting syntheses were analyzed by mass spectrometry. Relative to the controls (no radiation, or no formamide, or no catalyst), an extremely rich, variegate, and prebiotically relevant panel of compounds was observed. The meteorites tested were representative of the four major classes: iron, stony iron, chondrites, and achondrites. The products obtained were amino acids, carboxylic acids, nucleobases, sugars, and, most notably, four nucleosides: cytidine, uridine, adenosine, and thymidine. In accordance with theoretical studies, the detection of HCN oligomers suggests the occurrence of mechanisms based on the generation of radical cyanide species (CN·) for the synthesis of nucleobases. Given that many of the compounds obtained are key components of extant organisms, these observations contribute to outline plausible exogenous high-energy-based prebiotic scenarios and their possible boundary conditions, as discussed.

Keywords: formamide; meteorites; nucleosides; origin of life; prebiotic syntheses.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / chemical synthesis
  • Amino Acids / radiation effects
  • Carboxylic Acids / chemical synthesis
  • Carboxylic Acids / radiation effects
  • Catalysis
  • Evolution, Chemical*
  • Formamides / chemistry*
  • Formamides / radiation effects*
  • Meteoroids*
  • Models, Chemical
  • Molecular Structure
  • Nucleosides / chemical synthesis*
  • Nucleosides / radiation effects*
  • Origin of Life
  • Protons

Substances

  • Amino Acids
  • Carboxylic Acids
  • Formamides
  • Nucleosides
  • Protons
  • formamide