A Possible Primordial Peptide Cycle

Huber, Claudia
Eisenreich, Wolfgang
Hecht, Stefan
Wächtershäuser, Günter

¹Department for Organic Chemistry and Biochemistry, Technische Universität München, Lichtenbergstraße 4, D-85747 Garching, Germany. ²Tal 29, D-80331 München, Germany.

*To whom correspondence should be addressed. E-mail: [email protected]

Supporting Online Material: www.sciencemag.org/cgi/content/full/301/5635/938/DC1; Materials and Methods; Figs. S1 and S2

6 May 2003; accepted 1 July 2003

Science 301(5635):p 938-940, August 15, 2003.

α-Amino acids can undergo peptide formation by activation with carbon monoxide (CO) under hot aqueous conditions in the presence of freshly coprecipitated colloidal (Fe,Ni)S. We now show that CO-driven peptide formation proceeds concomitantly with CO-driven, N-terminal peptide degradation by racemizing N-terminal hydantoin and urea derivatives to α-amino acids. This establishes a peptide cycle with closely related anabolic and catabolic segments. The hydantoin derivative is a purin-related heterocycle. The (Fe,Ni)S-dependent urea hydrolysis could have been the evolutionary precursor of the nickel-enzyme urease. The results support the theory of a chemoautotrophic origin of life with a CO-driven, (Fe,Ni)S-dependent primordial metabolism.