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Desulfovibrio vulgaris Miyazaki F; density functional theory (DFT); electron nuclear double resonance (ENDOR); EPR; hydrogenase; hyperfine sublevel correlation (HYSCORE)
Abstract:
Isolation and purification of the [NiFe] hydrogenase of Desulfovibrio vulgaris Miyazaki F under aerobic conditions leads to a mixture of two states, Ni-A (unready) and Ni-B (ready). The two states are distinguished by different activation times and different EPR spectra. HYSCORE and ENDOR data and DFT calculations show that both states have an exchangeable proton, albeit with a different 1H hyperfine coupling. This proton is assigned to the bridging ligand between Ni and Fe. For Ni-B, a hydroxo ligand is found. For Ni-A, either a hydroxo in a different orientation or a hydroperoxo-bridging ligand is present.
