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Photoproduction of chiral amino acids under simulated interstellar conditions

Meierhenrich U.J., Muñoz Caro G.M., Schutte W.A., Barbier B., Arcones Segovia A., Rosenbauer H., Thiemann W., Brack A.

Abstract The interstellar medium ISMis known to be composed of both gas and dust particles. These dust particles are assumed to be made up of silicate grains, surrounded by an ice layer including carbon containing molecules. We simulated interstellar conditions in the laboratory in order to receive information on the interaction between the interstellar gas and interstellar dust particles. H20, CO2, CO, CH3OH, and NH3 were deposited at 12 K and a pressure of 10E-7 mbar onto a solid surface under irradiation of representative interstellar electromagnetic radiation. The ice layer developed on the solid surface was analysed by enantioselective gas chromatography and mass spectrometry GC-MS. In order to exclude contamination processes parallel experiments were performed with 13C-containing educts. After the analytical steps of extraction, hydrolysis, and derivatization 16 amino acids were identified in the simulated ice mantle of interstellar dust particles [1]. The results were confirmed by the 13C-experiments, definitely excluding contaminations. The chiral amino acids were identified as being totally racemic. The obtained results strongly suggest that amino acids had already been formed in the ISM. With the delivery of such precursor molecules through the bombardment of Earth with meteoritic resp. cometary material during the early history of Earth they might have contributed to prebiological reactions forming molecules being of crucial relevance
for processes in chemical evolution. 

Origins of Life and Evolution of the Biosphere 33 (2003), 257-258 .