Structural Insights into the Iron Nitrogenase Complex

Abstract

Nitrogenases are best known for catalysing the reduction of dinitrogen to ammonia at a complex metallic cofactor. Recently, nitrogenases were shown to reduce carbon dioxide (CO2) and carbon monoxide to hydrocarbons, offering a pathway to recycle carbon waste into hydrocarbon products. Among the nitrogenase family the iron nitrogenase is the isozyme with the highest wildtype activity for the reduction of CO2, but the molecular architecture facilitating these activities remained unknown. Here, we report a 2.35-Å cryogenic electron microscopy structure of the Fe nitrogenase complex from Rhodobacter capsulatus, revealing an [Fe8S9C-(R)-homocitrate]-cluster in the active site.