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IRIS è l'Anagrafe della ricerca dell'Università degli Studi di Trento, e ha lo scopo di raccogliere, documentare, conservare e diffondere, anche ad accesso aperto, la produzione scientifica degli autori afferenti all'Università degli Studi di Trento.

Wet-dry cycles driven by heating to high temperatures are frequently invoked for the prebiotic synthesis of peptides. Similarly, iron-sulfur clusters are often cited as an example of an ancient catalyst that helped prune early chemical systems into metabolic-like pathways. Because extant iron-sulfur clusters are metallocofactors of protein enzymes and nearly ubiquitous across biology, a reasonable hypothesis is that prebiotic iron-sulfur peptides formed on the early Earth. However, iron-sulfur clusters are coordinated by multiple cysteine residues, and the stability of cysteines to the heat steps of wet-dry cycles has not been determined. It, therefore, has remained unclear if the peptides needed to stabilize the formation of iron-sulfur clusters could have formed. If not, then iron-sulfur-dependent activity may have emerged later, when milder, more biological-like peptide synthesis machinery took hold. Here, we report the thermal stability of cysteine-containing peptides. We show that temperatures of 150 °C lead to the rapid degradation of cysteinyl peptides. However, the presence of Mg2+ at environmentally reasonable concentrations leads to significant protection. Thiophilic metal ions also protect against degradation at 150 °C but require concentrations not frequently observed in the environment. Nevertheless, cysteine-containing peptides are stable at lower, prebiotically plausible temperatures in seawater, carbonate lake, and ferrous lake conditions. The data are consistent with the persistence of cysteine-containing peptides on the early Earth in environments rich in metal ions. High concentrations of Mg2+ are common intra- and extra-cellularly, suggesting that the protection afforded by Mg2+ may reflect conditions that were present on the prebiotic Earth.

Prebiotic Environments with Mg2+and Thiophilic Metal Ions Increase the Thermal Stability of Cysteine and Non-cysteine Peptides / Rossetto, D.; Valer, L.; Yeh Martin, N.; Guella, G.; Hongo, Y.; Mansy, S. S.. - In: ACS EARTH AND SPACE CHEMISTRY. - ISSN 2472-3452. - STAMPA. - 6:5(2022), pp. 1221-1226-1226. [10.1021/acsearthspacechem.2c00042]

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