The Transformation by Catalysis of Prebiotic Chemical Systems to Useful Biochemicals: A Perspective Based on IR Spectroscopy of the Primary Chemicals: I. The Synthesis of Peptides by the Condensation of Amino Acids

Abstract

It is now widely speculated that life originated at the “Black Smokers” of the undersea hydrothermal vents, where conditions exist for the formation of the primary ingredients and their subsequent transformation to higher biotic species such as amino acids, alcohols, etc. Any possible routes for the prebiotic oligomerization of simple compounds like amino acids, necessary for cell formation, has so far not been well understood. However, Leman et al. recently reported that under standard laboratory conditions carbonyl sulfide (COS) can “mediate” the oligomerization of simple amino acids in moderate yield. COS being a well-known volcanic gas points to its possible role in prebiotic peptide formation in the environment of the hydrothermal vents. Based on a previously developed and tested model for selective (vibrational) energy transfer (SET), we show that a COS-catalyzed condensation of α-amino-acids can lead to the formation of polypeptides. We also indicate that other agents can act as catalysts of the amino acid condensation, such as Fe(CN)₆³⁻ and cyanamide (H₂N-CN). This is related to the existence of vibrations with a frequency near to that of the critical vibration of the reactant, ρ_w (NH₂). This wagging vibration occurs at 1048 ± 10 cm⁻¹ (the mean value of Cu and Ni complexes) and, as the vibration of the presumed catalyst lies at 2079 cm⁻¹, one notes that one quantum of the catalyst equals two quanta of the NH₂ wagging: 2079/2 × 1048 = 0.9919. This is a good indication of a resonance.