Single crystal EPR studies of the reduced active site of [NiFe] hydrogenase from Desulfovibrio vulgaris Miyazaki F

The issue concerning several matters in hydrogenase research, namely the formal oxidation states of nickel in all its paramagnetic intermediate state, the structure of the [NiFe] cluster, including the type of the third bridging ligand between the metals and the functional role of the active center of the enzyme in the hydrogen conversion process is addressed. The various experimental and theoretical considerations indicate a plausible assignment of the g tensors to a specific site.