The redox centers in the molybdo iron-sulfur flavoprotein CO dehydrogenase from the thermophilic carboxidotrophic bacterium Pseudomonas thermocarboxydovorans

Abstract

The redox centers in the molybdo iron-sulfur flavoprotein CO dehydrogenase from the thermophilic bacterium Pseudomonas thermocarboxydovorans were identified and characterized by electron paramagnetic resonance (EPR). One mol of the 279-kDa dimer contained 1.9 mol of Mo, 2.2 mol of FAD, 6.9 mol of Fe and 6.7 mol of labile sulfide. The molybdenum cofactor is composed of a 1:1 mononuclear complex of molybdopterin-cytosine dinucleotide and the Mo ion. EPR spectroscopy revealed signals typical for Mo(V), FADH , and type I and type II [2Fe-2S] centers.