Identification of diamino acids in the Murchison meteorite

doi:10.1073/pnas.0403043101

Identification of diamino acids in the Murchison meteorite

^*Department of Physical Chemistry, University of Bremen, FB 02, Leobener Strasse, 28359 Bremen, Germany; ^†Laboratoire de Chimie Bioorganique, Unité Mixte de Recherche 6001 CNRS–UNSA, Université de Nice-Sophia Antipolis, Faculté des Sciences, Parc Valrose, 06108 Nice Cedex 2, France; ^§Institut d'Astrophysique Spatiale, Campus d'Orsay, Bâtiment 121, 91405 Orsay Cedex, France; and ^¶Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Strasse 10, 48149 Münster, Germany

Communicated by Ewine F. van Dishoeck, Leiden University, Leiden, The Netherlands, April 30, 2004 (received for review February 11, 2004)

Abstract

Amino acids identified in the Murchison chondritic meteorite by molecular and isotopic analysis are thought to have been delivered to the early Earth by asteroids, comets, and interplanetary dust particles where they may have triggered the appearance of life by assisting in the synthesis of proteins via prebiotic polycondensation reactions [Oró, J. (1961) Nature 190, 389–390; Chyba, C. F. & Sagan, C. (1992) Nature 355, 125–132]. We report the identification of diamino acids in the Murchison meteorite by new enantioselective GC-MS analyses. dl-2,3-diaminopropanoic acid, dl-2,4-diaminobutanoic acid, 4,4′-diaminoisopentanoic acid, 3,3′-diaminoisobutanoic acid, and 2,3-diaminobutanoic acid were detected in the parts per billion range after chemical transformation into N,N-diethoxycarbonyl ethyl ester derivatives. The chiral diamino acids show a racemic ratio. Laboratory data indicate that diamino acids support the formation of polypeptide structures under primitive Earth conditions [Brack, A. & Orgel, L. E. (1975) Nature 256, 383–387] and suggest polycondensation reactions of diamino acids into early peptide nucleic acid material as one feasible pathway for the prebiotic evolution of DNA and RNA genomes [Joyce, G. F. (2002) Nature 418, 214–221]. The results obtained in this study favor the assumption that not only amino acids (as the required monomers of proteins) form in interstellar/circumstellar environments, but also the family of diamino monocarboxylic acids, which might have been relevant in prebiotic chemistry.

Footnotes

↵ ‡ To whom correspondence should be addressed at: Department of Physical Chemistry, University of Bremen, Fachbereich 2, Building NW 2, Room B 1156, Leobener Strasse, 28359 Bremen, Germany, or the † address. E-mail: mhenrich{at}uni-bremen.de or mhenrich{at}unice.fr.
Abbreviations: amu, atomic mass units; ECEE, N,N′-diethoxycarbonyl diamino acid ethyl ester; PNA, peptide nucleic acid; ppb, parts per billion.