Experimentelle und Analytische Planetologie
Identification of diamino acids in the Murchison meteorite
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.
Drittmittelgeber:
Beteiligte Wissenschaftler:
Veröffentlichungen:
|
