title: A possible primordial peptide cycle.
abstract: alpha-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 alpha-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 nickelenzyme urease. The results support the theory of a chemoautotrophic origin of life with a CO-driven, (Fe,Ni)S-dependent primordial metabolism.
authors.affiliation: Department for Organic Chemistry and Biochemistry, Technische Universität München, Lichtenbergstrabetae 4, D-85747 Garching, Germany.
authors.forename: Claudia
authors.initials: C
authors.lastname: Huber
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Eisenreich
authors.forename: Stefan
authors.initials: S
authors.lastname: Hecht
authors.forename: Gunter
authors.initials: G
authors.lastname: Wächtershäuser
mesh_terms: D000596:Amino Acids / Q000737:chemistry / Q000378:metabolism*; D002245:Carbon Dioxide / Q000737:chemistry / Q000378:metabolism; D002248:Carbon Monoxide / Q000737:chemistry / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004151:Dipeptides / Q000737:chemistry / Q000378:metabolism; D019418:Evolution, Chemical; D005296:Ferrous Compounds / Q000737:chemistry / Q000378:metabolism; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D013058:Mass Spectrometry; D009532:Nickel / Q000737:chemistry / Q000378:metabolism; D000069497:Origin of Life; D010084:Oxidation-Reduction; D010455:Peptides / Q000737:chemistry / Q000378:metabolism*; D010649:Phenylalanine / Q000737:chemistry / Q000378:metabolism*; D011312:Pressure; D013237:Stereoisomerism; D014508:Urea / Q000737:chemistry / Q000378:metabolism; D014510:Urease / Q000737:chemistry / Q000378:metabolism
chemical_list: D000596:Amino Acids; D004151:Dipeptides; D005296:Ferrous Compounds; D010455:Peptides; D002245:Carbon Dioxide; C026650:phenylalanylphenylalanine; D010649:Phenylalanine; D009532:Nickel; D002248:Carbon Monoxide; D014508:Urea; D014510:Urease; C017558:nickel sulfide; C022597:ferrous sulfide