Hydride intermediates in the catalytic turnover of gas-processing metalloenzymes from diverse microorganisms

Understanding the structure and molecular mechanism of low-valent gas-processing metalloenzymes (GPMs) inspires the design of synthetic catalysts for H₂ production, N₂ fixation, and the removal of CO₂ from the atmosphere.

Based on insight from structural biology and vibrational spectroscopy, I will discuss the molecular mechanism of GPMs like hydrogenase and nitrogenase. Second and outer coordination sphere effects critically promote metal-hydride species that are key to H₂ production with zero electric overpotential and N₂ fixation under ambient conditions. While typically O₂-senstitive, the combination of high substrate affinity and dynamic gas filtering enables certain hydrogenases to catalyse H₂ oxidation “out of thin air” (pH₂ <0.00005%).