PREBIOTIC CHEMISTRY Prebiotic Synthesis of Methionine and Other Sulfur-Containing Organic Compounds on the Primitive Earth: A Contemporary Reassessment Based on an Unpublished 1958 Stanley Miller Experiment

Original extracts from an unpublished 1958 experiment conducted by the late Stanley L. Miller were recently found and analyzed using modern state-of-the-art analytical methods. The extracts were produced by the action of an electric discharge on a mixture of methane (CH4), hydrogen sulfide (H2S), ammonia (NH3), and carbon dioxide (CO2). Racemic methionine was formed in significant yields, together with other sulfur-bearing organic compounds. The formation of methionine and other compounds from a model prebiotic atmosphere that contained H2S suggests that this type of synthesis is robust under reducing conditions, which may have existed either in the global primitive atmosphere or in localized volcanic environments on the early Earth. The presence of a wide array of sulfurcontaining organic compounds produced by the decomposition of methionine and cysteine Orig Life Evol Biosph DOI 10.1007/s11084-010-9228-8 E. T. Parker : J. L. Bada Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA 92093, USA H. J. Cleaves Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Rd. NW, Washington, DC 20015, USA M. P. Callahan : J. P. Dworkin :D. P. Glavin NASA Goddard Space Flight Center, Solar System Exploration Division, Greenbelt, MD 20771, USA A. Lazcano Facultad de Ciencias, UNAM, Apdo. Postal 70-407 Cd. Universitaria, 04510 Mexico D. F., Mexico J. L. Bada (*) Scripps Institution of Oceanography, University of California at San Diego, 8615 Kennel Way, La Jolla, CA 92093-0212, USA e-mail: [email protected] Present Address: E. T. Parker School of Earth & Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA 30332, USA indicates that in addition to abiotic synthetic processes, degradation of organic compounds on the primordial Earth could have been important in diversifying the inventory of molecules of biochemical significance not readily formed from other abiotic reactions, or derived from extraterrestrial delivery.