| Item type: | Article | ||||
|---|---|---|---|---|---|
| Journal or Publication Title: | Archives of Microbiology | ||||
| Publisher: | SPRINGER-VERLAG | ||||
| Place of Publication: | NEW YORK | ||||
| Volume: | 173 | ||||
| Number of Issue or Book Chapter: | 4 | ||||
| Page Range: | pp. 233-244 | ||||
| Date: | 2000 | ||||
| Institutions: | Biology, Preclinical Medicine > Institut für Pflanzenwissenschaften > Lehrstuhl für Zellbiologie und Pflanzenphysiologie (Prof. Dr. Klaus Grasser) Biology, Preclinical Medicine > Institut für Biochemie, Genetik und Mikrobiologie > Lehrstuhl für Mikrobiologie (Archaeenzentrum) | ||||
| Identification Number: |
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| Keywords: | PURPLE PHOTOTROPHIC BACTERIUM; INORGANIC SULFUR-COMPOUNDS; RHODOBACTER-CAPSULATUS; FLAVOCYTOCHROME-C; PARACOCCUS-DENITRIFICANS; OSCILLATORIA-LIMNETICA; OXIDIZING BACTERIUM; CHROMATIUM-VINOSUM; REDUCTASE-ACTIVITY; ELEMENTAL SULFUR; Aquifex aeolicus; sulfide oxidation; sulfide : quinone oxidoreductase hyperthermophiles; cytochrome bc complex | ||||
| Dewey Decimal Classification: | 500 Science > 570 Life sciences 500 Science > 580 Botanical sciences | ||||
| Status: | Published | ||||
| Refereed: | Yes, this version has been refereed | ||||
| Created at the University of Regensburg: | Yes | ||||
| Item ID: | 74327 |
Web of ScienceAbstract
The sulfide-dependent reduction of exogenous ubiquinone by membranes of the hyperthermophilic chemotrophic bacterium Aquifex aeolicus (VF5), the sulfide-dependent consumption of oxygen and the reduction of cytochromes by sulfide in membranes were studied. Sulfide reduced decyl-ubiquinone with a maximal rate of up to 3.5 mu mol (mg protein)(-1) min(-1) at 20 degreesC. Rates of 220 nmol (mg ...
Abstract
The sulfide-dependent reduction of exogenous ubiquinone by membranes of the hyperthermophilic chemotrophic bacterium Aquifex aeolicus (VF5), the sulfide-dependent consumption of oxygen and the reduction of cytochromes by sulfide in membranes were studied. Sulfide reduced decyl-ubiquinone with a maximal rate of up to 3.5 mu mol (mg protein)(-1) min(-1) at 20 degreesC. Rates of 220 nmol (mg protein)-1 min-1 for the sulfide-dependent consumption of oxygen and 480 nmol (mg protein)(-1) min(-1) for the oxidation of sulfide at 20 degreesC were estimated. The reactions were sensitive towards 2-n-nonyl-4-hydroxyquinoline-N-oxide, but insensitive towards cyanide. Both reduction of decyl-ubiquinone and consumption of oxygen by sulfide rapidly increased with increasing temperature. For the sulfide-dependent respiratory activity, a sulfide-to-oxygen ratio of 2.3+/-0.2 was measured. This indicates that sulfide was oxidized to the level of zero-valent sulfur. Reduction of cytochromes by sulfide was monitored with an LED-array spectrophotometer. Reduction of cytochrome b was stimulated by 2-n-nonyl-4-hydroxyquinoline-N-oxide in the presence of excess sulfide under oxic conditions. This "oxidant-induced reduction" of cytochrome b suggests that electron transport from sulfide to oxygen in A. aeolicus employs the cytochrome bc complex via the quinone pool. Comparison of the amino acid sequence with the sequence of the sulfide:quinone oxidoreductase from Rhodobacter capsulatus and the flavocytochrome c from Allochromatium vinosum revealed that the sulfide:quinone oxidoreductase from A. aeolicus belongs to the glutathione reductase family of flavoproteins.
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