EPR characterization of soluble fragments of succinate dehydrogenase from mutant strains of Bacillus subtilis.
Succinate dehydrogenase is a membrane-bound metallo-flavo-enzyme containing a bi- (S-1), a tri- (S-3) and a tetranuclear (S-2) iron-sulfur cluster. The catalytic portion of the enzyme contains two distinct subunits designated Fp and Ip. Using concentrated extracts from mutant strains of Bacillus subtilis it was demonstrated, by using low temperature EPR, that cluster S-2 can be assembled in a soluble succinate dehydrogenase. In a mutant with a truncated Ip subunit which lacks 7 of the 11 conserved cysteine residues, cluster S-1 lacked the spin relaxation properties attributable to an adjacent cluster S-2. These data are consistent with a model where one or more cysteine residues from the middle set of 4 conserved cysteines in the Ip subunit are ligands to the tetranuclear cluster.
Maguire
J J
JJ
Lawrence Berkeley Laboratory, University of California, Berkeley 94720.
Hederstedt
L
L
D001412:Bacillus subtilis / Q000201:enzymology* / Q000235:genetics; D003545:Cysteine / Q000032:analysis; D004578:Electron Spin Resonance Spectroscopy; D009154:Mutation; D010446:Peptide Fragments / Q000032:analysis* / Q000235:genetics; D012995:Solubility; D013385:Succinate Dehydrogenase / Q000032:analysis* / Q000235:genetics; D013696:Temperature
D010446:Peptide Fragments; D013385:Succinate Dehydrogenase; D003545:Cysteine