Jeffrey Bada e equipe refazem o experimento de Urey-Miller: "Correr atrás do vento 2"

quarta-feira, março 23, 2011

Primordial synthesis of amines and amino acids in a 1958 Miller H2S-rich spark discharge experiment

Eric T. Parker a,1, Henderson J. Cleaves b, Jason P. Dworkin c, Daniel P. Glavin c, Michael Callahan c, Andrew Aubrey d, Antonio Lazcano e, and Jeffrey L. Bada a,2 

-Author Affiliations

aGeosciences Research Division, Scripps Institution of Oceanography, University of California at San Diego, 8615 Kennel Way, La Jolla, CA 92093;
bGeophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Road NW, Washington, DC 20015;
cNational Aeronautics and Space Administration Goddard Space Flight Center, Solar System Exploration Division, Greenbelt, MD 20771;
dNational Aeronautics and Space Administration Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109; and
eFacultad de Ciencias, Universidad Nacional Autónoma de México, Apdo. Postal 70-407 Ciudad Universitaria, 04510 Mexico D.F., Mexico

Edited by Gerald F. Joyce, The Scripps Research Institute, La Jolla, CA, and approved February 14, 2011 (received for review December 22, 2010)



Abstract

Archived samples from a previously unreported 1958 Stanley Miller electric discharge experiment containing hydrogen sulfide (H2S) were recently discovered and analyzed using high-performance liquid chromatography and time-of-flight mass spectrometry. We report here the detection and quantification of primary amine-containing compounds in the original sample residues, which were produced via spark discharge using a gaseous mixture of H2S, CH4, NH3, and CO2. A total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples. The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordial environments. The relative yield of some amino acids, in particular the isomers of aminobutyric acid, are the highest ever found in a spark discharge experiment. The simulated primordial conditions used by Miller may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H2S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H2S may have played an important role in prebiotic reactions in early solar system environments.

prebiotic chemistry, volcano plume chemistry, carbonaceous chondrites

Footnotes


1Present address: School of Earth and Atmospheric Sciences, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332.

2To whom correspondence should be addressed. E-mail:jbada@ucsd.edu.

Author contributions: J.L.B. designed research; E.T.P., H.J.C., J.P.D., D.P.G., M.C., and J.L.B. performed research; E.T.P., H.J.C., J.P.D., D.P.G., and M.C. contributed new reagents/analytic tools; E.T.P., H.J.C., J.P.D., D.P.G., M.C., A.A., A.L., and J.L.B. analyzed data; and E.T.P., H.J.C., J.P.D., D.P.G., A.L., and J.L.B. wrote the paper; .

The authors declare no conflict of interest.

This article is a PNAS Direct Submission.

This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1019191108/-/DCSupplemental.

Freely available online through the PNAS open access option.

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