DFT-modeling of the tungsten (V) cofactor of hyperthermophilic Pyrococcus furiosus tungsto-bispterin enzyme via the calculated EPR parameters

Here we report a DFT relativistic scalar and spin–orbit study that considers the structural optimization of the complete tungsten (V) cofactor by studying the paramagnetic site of the Pyrococcus furiosus tungsto-bispterin enzyme. The best-fit superimposed X-ray structure shows an important similarity with the aldehyde ferredoxin oxidoreductase (1AOR) structure, and, the W(V) cofactor exhibits a Kramers doublet as the ground state, which agrees with the EPR observations. We conclude that it is quite necessary to include relativistic scalar and spin–orbit effects to describe the whole tungsten (V) cofactor in the P. furiosus tungsto-bispterin enzyme.