Iron and oxygen are central to terrestrial life. Aqueous iron and oxygen chemistry will
produce a ferric ion trillions of times less soluble than cell iron concentrations, along with
radical forms of oxygen that are toxic. In the physiological environment, many proteins have
evolved to transport iron or modulate the redox chemistry of iron that transforms oxygen in
useful biochemical reactions. Only one protein, ferritin, evolved to concentrate iron to levels
needed in aerobic metabolism. Reversible formation and dissolution of a solid nanomineral …