Activation of CO2 by Vanadium Nitrogenase

The reduction of CO2 into useful products, including hydrocarbon fuels, is an ongoing area of particular interest due to efforts to mitigate buildup of this greenhouse gas. While the industrial Fischer-Tropsch process can facilitate the hydrogenation of CO2 with H-2 to form short-chain hydrocarbon products under high temperatures and pressures, a desire to perform these reactions under ambient conditions has inspired the use of biological approaches. Particularly, enzymes offer insight into how to activate and reduce CO2, but only one enzyme, nitrogenase, can perform the multielectron, multiproton reduction of CO2 into hydrocarbons. The vanadium-containing variant, V-nitrogenase, displays especial reactivity towards the hydrogenation of CO and CO2. This Focus Review discusses recent progress towards the activation and reduction of CO2 with three primary V-nitrogenase systems. These systems span both ATP-dependent and ATP-independent processes and utilize approaches with whole cells, isolated proteins, and extracted cofactors.