LAUSR

The Mo and V nitrogenases are structurally homologous yet catalytically distinct in their abilities to reduce CO to hydrocarbons. Here we report a comparative analysis of the CO‐reducing activities of the Mo‐ and V‐nitrogenase cofactors (i.e., the M and V clusters) upon insertion of the respective cofactor into the same, cofactor‐deficient MoFe protein scaffold. Our data reveal a combined contribution from the protein environment and cofactor properties to the reactivity of nitrogenase toward CO, thus laying a foundation for further mechanistic investigation of the enzymatic CO reduction, while suggesting the potential of targeting both the protein scaffold and the cofactor species for nitrogenase‐based applications in the future.