Nitrogenases-A Tale of Carbon Atom(s)

Named after its ability to catalyze the reduction of nitrogen to ammonia, nitrogenase has a surprising rapport with carbon—both through the interstitial carbide that resides in the central cavity of its cofactor and through its ability to catalyze the reductive carbon–carbon coupling of small carbon compounds into hydrocarbon products. Recently, a radical‐SAM‐dependent pathway was revealed for the insertion of carbide, which signifies a novel biosynthetic route to complex bridged metalloclusters. Moreover, a sulfur‐displacement mechanism was proposed for the activation of carbon monoxide by nitrogenase, which suggests an essential role of the interstitial carbide in maintaining the stability while permitting a certain flexibility of the cofactor structure during substrate turnover. A close rapport exists between nitrogenase and carbon through the interstitial carbide of the cofactor of nitrogenase and through the ability of nitrogenase to reduce small carbon compounds to hydrocarbons. Recent advances reveal a radical‐SAM‐dependent mechanism of carbide insertion into the nitrogenase cofactor and suggest a role of the interstitial carbide in maintaining the stability while permitting certain flexibility of the cofactor structure during catalysis.