2020 Volume 129 Issue 6 Pages 853-870
The origin of life has been explained by a number of hypotheses. Depending on the geochemical settings in each hypothesis, model metabolisms of the first life are classified into two major types, namely, heterotrophy and autotrophy. The “Iron-sulfur world” hypothesis explains the development of autotrophic life with a chemical evolution process mediated by metal sulfides. Metal sulfides have been found to catalyze simple carbon/nitrogen reduction reactions in simulated Hadean Earth conditions. Combinations of these reactions are thought to form organic molecules, such as pyruvate and peptide, then ultimately the first cell. Iron-sulfur proteins are found in all life and play a cardinal role in key redox/oxidation reactions, such as carbon/nitrogen fixation, respiration, and translation. Ancient iron-sulfur proteins are hypothesized to be formed by the conjugation of iron-sulfur clusters and simple peptides. First, an overview is given of the “Iron-sulfur world” hypothesis including the chemical evolution process for the formation of ancient iron-sulfur proteins, and then future perspectives for the origin-of-life research are discussed in the context of this hypothesis.
