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Amino acids from ultraviolet irradiation of interstellar ice analogues


Amino acids are the essential molecular components of living organisms on Earth, but the proposed mechanisms for their spontaneous generation have been unable to account for their presence in Earth's early history1. The delivery of extraterrestrial organic compounds has been proposed as an alternative to generation on Earth2,3,4,5, and some amino acids have been found in several meteorites6,7,8,9. Here we report the detection of amino acids in the room-temperature residue of an interstellar ice analogue that was ultraviolet-irradiated in a high vacuum at 12 K. We identified 16 amino acids; the chiral ones showed enantiomeric separation. Some of the identified amino acids are also found in meteorites. Our results demonstrate that the spontaneous generation of amino acids in the interstellar medium is possible, supporting the suggestion that prebiotic molecules could have been delivered to the early Earth by cometary dust, meteorites or interplanetary dust particles.

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Figure 1: Gas chromatogram showing the amino acids and other compounds generated under simulated interstellar pre-cometary conditions.


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We thank A. MacDermott, F. Goesmann and R. Roll for discussions and K. Getliffe for suggestions. Our collaboration was originally supported by the Max-Planck-Institut für Aeronomie at Katlenburg-Lindau with grants for G.M.M.C. and U.J.M., as preparatory work for the Rosetta mission. The work was performed at the Sackler Laboratory for Astrophysics at Leiden Observatory and the Centre Biophysique Moléculaire at Orléans, where it was funded by the European Union and by French sponsors: CNES, FNAD, Région Centre, and Département du Cher. In Orléans U.J.M. was supported by a Le Studium grant. U.J.M. is grateful for a habilitation grant by the Deutsche Forschungsgemeinschaft, and G.M.M.C. for an AIO allowance by Leiden University. This paper is dedicated to the memory of J.M.G., who died on 29 November 2001.

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Muñoz Caro, G., Meierhenrich, U., Schutte, W. et al. Amino acids from ultraviolet irradiation of interstellar ice analogues. Nature 416, 403–406 (2002).

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