Mineral spirits: CH4 oxidation and CO2 reduction by Green rust minerals yields pathways to emergence of life

Structural homology between reactive minerals and enzymatic metal cofactors hints at mechanistic and possibly evolutionary links between reactive abiotic structures and biological metabolism. The octahedral coordination of reactive Fe2+/3+ minerals such as green rusts, endemic to anoxic sediments and the early Earth’s oceans, mirrors the di-iron reaction center of enzymes such as soluble methane monooxygenase (sMMO), responsible for methane oxidation in methanotrophy. We add further evidence to our recent findings on green rust mediated CH4 oxidation and CO2 reduction and propose that these naturally occurring geochemical pathways for carbon redox elucidates an evolutionary link between geochemical mineral-mediated organic synthesis and the biochemical synthesis of organic compounds necessary for life.