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Wolinella succinogenes fumarate reductase contains a dihaem cytochrome b
Author(s) -
Körtner C.,
Lauterbach F.,
Tripier D.,
Unden G.,
Kröger A.
Publication year - 1990
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1990.tb00657.x
Subject(s) - biology , biochemistry , cytochrome b , escherichia coli , operon , histidine , cytochrome , fumarate reductase , reductase , peptide sequence , enzyme , amino acid , gene , microbiology and biotechnology , mitochondrial dna
Summary 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.