O2-independent formation of the inactive states of NiFe hydrogenase

Abstract

We studied the mechanism of aerobic inactivation of Desulfovibrio fructosovorans nickel-iron (NiFe) hydrogenase by quantitatively examining the results of electrochemistry, EPR and FTIR experiments. They suggest that, contrary to the commonly accepted mechanism, the attacking O2 is not incorporated as an active site ligand but, rather, acts as an electron acceptor. Our findings offer new ways toward the understanding of O2 inactivation and O2 tolerance in NiFe hydrogenases.