Wolinella succinogenes fumarate reductase contains a dihaem cytochrome b.
The fumarate reductase operon of Wolinella succinogenes is made up of three structural genes (frd-CAB). The frdC gene was located next to the promoter region and identified as the cytochrome b structural gene encoding 256 amino acid residues. The N-terminal amino acid sequences of seven fragments derived from the cytochrome b moiety of the enzyme all mapped within the frdC gene. This suggested that the enzyme contained only one species of cytochrome b. Re-evaluation of earlier measurements of subunit composition, haem B content and molecular weight led to the conclusion that the enzyme contained one molecule of cytochrome b with two haem B groups. The hydropathy plot of the amino acid sequence predicted five membrane-spanning hydrophobic segments, the first four of which contained a single histidine residue each. These residues could form the axial ligands to the two haem B groups. FrdC was found to be homologous with the cytochrome b (SdhC) of the Bacillus subtilis succinate dehydrogenase, but not with the hydrophobic subunits of the fumarate reductase or succinate dehydrogenase of Escherichia coli.
Körtner
C
C
Institut für Mikrobiologie, J. W. Goethe-Universität, Frankfurt, FRG.
Lauterbach
F
F
Tripier
D
D
Unden
G
G
Kröger
A
A
D000595:Amino Acid Sequence; D001483:Base Sequence; D003573:Cytochrome b Group / Q000235:genetics*; D004269:DNA, Bacterial / Q000032:analysis; D005798:Genes, Bacterial; D006418:Heme / Q000378:metabolism; D008969:Molecular Sequence Data; D009876:Operon; D015183:Restriction Mapping; D013385:Succinate Dehydrogenase / Q000235:genetics*; D014158:Transcription, Genetic; D014733:Vibrio / Q000235:genetics*
D003573:Cytochrome b Group; D004269:DNA, Bacterial; D006418:Heme; D013385:Succinate Dehydrogenase