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Résumé

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Origins of life studies represent an exciting and highly multidisciplinary research field that incorporates contributions from geologists, physicists, biologists, mathematicians, chemists and computer scientists, inter alia. It was Charles Darwin who first hypothesized that life may have begun “in a warm little pond, with all sorts of ammonia and phosphoric salts, lights, heat, electricity”, effectively giving birth to the “primordial soup hypothesis”. In 1953, Miller reported the stunning results of an electric discharge on a model atmosphere for the primitive Earth. The surprising result of this experiment was a substantial yield of a mixture of amino acids, thus providing support for the primitive soup theory. However, the chemical reactions involved in those experiments have never been studied at the fundamental atomic and electronic level. Here we present the first ab initio theoretical simulations of Miller experiments. This study, based on state-of-the-art ab initio metadynamics analysis of free-energy landscapes, shows that glycine spontaneously forms from mixtures of simple molecules once an electric field is switched on and identifies formic acid and formamide as key intermediate products of the early steps of the Miller reactions, and the crucible of formation of complex biological molecules. These results, which have had a large resonance in the scientific and large public press, pave the way to novel computational approaches in the research of the chemical origins of life.

Note(s) Biographique(s)

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Bibliographie

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Orateur(s) : A. Marco Saitta
Public : Tous
Date : 10 Mars 2015
Lieu : Campus Jussieu