Peptide Formation in the Prebiotic Era: Thermal Condensation of Glycine in Fluctuating Clay Environments

Abstract

As geologically relevant models of prebiotic environments, systems consisting of clay, water, and amino acids were subjected to cyclic variations in temperature and water content. Fluctuations of both variables produced longer oligopeptides in higher yields than were produced by temperature fluctuations alone. The results suggest that fluctuating environments provided a favorable geological setting in which the rate and extent of chemical evolution would have been determined by the number and frequency of cycles.

The Formation and Self‐Assembly of Long Prebiotic Oligomers Produced by the Condensation of Unactivated Amino Acids on Oxide Surfaces

“…Due to its ability to adsorb a larger quantity of Gly, with the consequent advantages for analyzing the products, TiO 2 was also sequentially exposed to Gly and Glycine-1-13 C ( 13 Gly) vapors. The detection of (Gly) n -( 13 Gly) m oligomers (see Figure S4 and Table S1 in the SI) clearly indicated the effectiveness of successive monomer "feedings," similar to the polymerization of activated amino acids and nucleotides on minerals performed by Ferris et al [1] Based on the idea of "fluctuating environments", [23] Gly/SiO 2 and Gly/TiO 2 systems with as-formed polyglycines were exposed to water vapor to investigate the molecular surface events that occur upon hydration. Figure 3 presents the results of the in situ IR study of the evolution of Gly/TiO 2 , while those obtained for the Gly/SiO 2 are reported in Figure S5 in the SI.…”

Stochastic Prebiotic Chemistry within Realistic Geological Systems

“…Studies provide evidence for the ability of clay minerals to concentrate and polymerise amino acids, e.g. glycine to the pentamer (e.g., [111,112] ). Hanczyc and colleagues [113] encapsulated RNA in vesicles chelated to clay minerals after mixing RNA with lipids and clays.…”

5. Prebiotic Chemistry – Biochemistry – Emergence of Life (4.4–2 Ga)

“…Hypothetical places that would have been favourable can be inferred from the processes leading to the accumulation of organic matter in a specific environment. For instance, as soon as emerged lands were present, it can be devised that ocean tides (induced by the vicinity of the Moon) may have allowed the formation of pools concentrating monomers and may have triggered wetting/drying cycles capable of inducing their polymerization possibly with the assistance of minerals (Rohlfing, 1976, Lahav et al, 1978, Rode et al 1999. They may also have induced solid-gas reactions that have been shown to induce peptide bond formation (Commeyras et al, 2002).…”