Bacillus subtilis mutant succinate dehydrogenase lacking covalently bound flavin: Identification of the primary defect and studies on the iron-sulfur clusters in mutated and wild- type enzyme
Succinate dehydrogenase consists of two protein subunits and contains one FAD and three iron-sulfur clusters. The flavin is covalently bound to a histidine in the larger, Fp, subunit. The reduction oxidation midpoint potentials of the clusters designated S-l, S-2, and S-3 in Bacillus subtilis wild-type membrane-bound enzyme were determined as +80, -240, and -25 mV, respectively. Magnetic spin inte