2025/01/19 by Melanie Heghmanns, Shalini Yadav, Sergius Boschmann +6 · 1 voice · 2 citations
Energy · Chemical Engineering · #Metalloenzymes and iron-sulfur proteins #Electrocatalysts for Energy Conversion #Ammonia Synthesis and Nitrogen Reduction
paper · pdf · doi:10.1002/anie.202424167
Abstract Iron‐sulfur clusters play a crucial role in electron transfer for many essential enzymes, including [FeFe]‐hydrogenases. This study focuses on the [4Fe4S] cluster ([4Fe] H ) of the minimal [FeFe]‐hydrogenase from Chlamydomonas reinhardtii ( Cr HydA1) and employs advanced spectroscopy, site‐directed mutagenesis, molecular dynamics simulations, and QM/MM calculations. We provide insights into the complex electronic structure of [4Fe] H and its role in the catalytic reaction of Cr HydA1, serving as paradigm for understanding [FeFe]‐hydrogenases. We identified at least two distinct species within the apo‐form of Cr HydA1, designated 4Fe−R and 4Fe−A, with unique redox potentials and pH sensitivities. Our findings revealed that these species arise from a complex interplay of structural heterogeneity and valence isomer rearrangements, influenced by second‐sphere residues. We propose that the interconversion between 4Fe−R and 4Fe−A could provide control over electron transfer in the absence of accessory FeS clusters typically found in other [FeFe]‐hydrogenases. The insights gained from this study not only enhance our understanding of [FeFe]‐hydrogenases but also provide a crucial foundation for future investigations into analysis of other FeS clusters across diverse biological systems.