A thermodynamics-compliant emergence of life driven by redox free energy and mediated by soft, transition-metal-bearing layered nano-structures – deltaG2Life

Life and its emergence fundamentally depend on the conversion of environmental free energy into cellular decrease of entropy – a stricture imposed by the 2nd law of thermodynamics. This biological free energy conversion (bioenergetics) is performed by an ensemble of metalloenzymes which carry out intricate cascades of proton-coupled redox processes resulting in the generation of chemical free energy in the form of phosphorylation disequilibria. Purely inorganic, mineral-based precursors to bioenergetic systems have been discussed in the past. A particularly intriguing example of such minerals is the mixed-valence-iron-containing layered oxyhydroxide nano-mineral Green Rust (GR). GR features structural similarities to the catalytic metal-centres in a large class of metalloenzymes. In this project, we propose to investigate the catalytic reactivities, electron transfer properties as well as proton-electron coupled redox reactions performed by different versions of GR relevant to plausible conditions that prevailed on the early Earth. To tackle these questions, we have constituted a trans-disciplinary team comprising expertise from bioenergetics, nano-sciences, mineralogy and biogeochemistry. Results from this project will (a) improve our understanding of the properties of soft, clay-like, redox-active nano-minerals and (b) empirically test a specific hypothesis for the emergence of life from entirely inorganic settings.