Proton-Electron Dynamics in Fe-N2ase: Mechanistic Dissection by Advanced Spectroscopy

Objective

To achieve sustainable food production and green chemistry, new catalytic strategies are needed for N2 fixation and CO2 utilization. Nitrogenases (N2ases) offers an outstanding natural example, operating N2 fixation under ambient conditions. Among them, Fe-N2ase is particularly intriguing. It produces more H2 than Mo-N2ase and uniquely reduces CO2 to CH4. Yet, the catalytic principles of its active site, FeFeco, remain unresolved. Understanding how FeFeco orchestrates proton-electron transfer is key to uncovering rules of biological catalysis and inspiring new approaches to NH3 synthesis, H2 evolution, and CO2 reduction. ProFeN aims to deliver the first systematic dissection of proton-electron transfer pathways in Fe-N2ase. The project focuses on early intermediates during N2 fixation, where FeFeco accepts and distributes protons and electrons. Intermediates will be trapped and quantified, extending methodologies established for Mo-N2ase. Their structural and electronic dynamics will be then resolved using a complementary spectroscopic toolkit, including CW/pulsed EPR and HERFD-XAS/XES, coupled with multivariate data analysis and a tiered DFT-WFT computational framework. Site-selective Se substitution at sulfides will add atomic-level insight, enabling direct correlation of Fe- and ligand-centered changes with catalytic function. The outcome will be a comprehensive mechanistic framework for Fe-N2ase and a transferable toolkit for studying complex metalloenzymes and designing bio-inspired catalysts. Beyond scientific advances, ProFeN will equip the fellow with interdisciplinary expertise and transferable skills in project management, mentoring, leadership and international collaboration. This positions her for a tenure-track academic career in enzymatic and heterogeneous catalysis and to lead future efforts in sustainable, bio-inspired chemical transformations.