A Mössbauer spectroscopic investigation of the redox behaviour of the molybdenum-iron protein from Klebsiella pneumoniae nitrogenase. Mechanistic and structural implications

The redox properties of the nitrogenase Mo-Fe protein from Klebsiella pneumoniae have been monitored by 57Fe Mössbauer spectroscopy between -460 and -160mV (relative to the normal hydrogen electrode). Two redox processes associated with the atoms of the protein were observed. One at -216mV (pH 8.7) was associated with the Fe-Mo cofactor centres in the protein and allowed identification of the Mössbauer parameters of the oxidized form of these …