Prebiotic Environmental Conditions Impact the Type of Iron-Sulfur Cluster Formed

Iron-sulfur clusters are ancient cofactors that could have played a role in the prebiotic chemistry leading to the emergence of protometabolism. Previous research has shown that certain iron-sulfur clusters can form from prebiotically plausible components, such as cysteine-containing oligopeptides. However, it is unclear if these iron-sulfur clusters could have survived in prebiotically plausible environments. To begin exploring this possibility, we tested the stability of iron-sulfur clusters coordinated to a tripeptide and to N-acetyl-L-cysteine methyl ester in a variety of solutions meant to mimic prebiotically plausible environments. We also assessed the impact of individual chemical components on stability. We find that iron-sulfur clusters form over a wide variety of conditions but that the type of iron-sulfur cluster formed is strongly impacted by the chemical environment and the coordinating scaffold. These findings support the general hypothesis that iron-sulfur clusters were present on the prebiotic Earth and that different types of iron-sulfur cluster predominated in different environments.