Coupling of the pathway of sulphur oxidation to dioxygen reduction

Characterization of a novel membrane-bound thiosulphate:quinone oxidoreductase

Fabian H. Müller, Tiago M. Bandeiras, Tim Urich, Miguel Teixeira, Cláudio M. Gomes, Arnulf Kletzin

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103 Citations (Scopus)

Abstract

Thiosulphate is one of the products of the initial step of the elemental sulphur oxidation pathway in the thermoacidophilic archaeon Acidianus ambivalens. A novel thiosulphate:quinone oxidoreductase (TQO) activity was found in the membrane extracts of aerobically grown cells of this organism. The enzyme was purified 21-fold from the solubilized membrane fraction. The TQO oxidized thiosulphate with tetrathionate as product and ferricyanide or decyl ubiquinone (DQ) as electron acceptors. The maximum specific activity with ferricyanide was 73.4 U (mg protein)-1 at 92°C and pH 6, with DQ it was 397 mU (mg protein)-1 at 80°C. The Km values were 2.6 mM for thiosulphate (kcat = 167 s-1), 3.4 mM for ferricyanide and 5.87 μM for DQ. The enzymic activity was inhibited by sulphite (Ki = 5 μM), metabisulphite, dithionite and TritonX-100, but not by sulphate or tetrathionate. A mixture of caldariella quinone, sulfolobus quinone and menaquinone was non-covalently bound to the protein. No other cofactors were detected. Oxygen consumption was measured in membrane fractions upon thiosulphate addition, thus linking thiosulphate oxidation to dioxygen reduction, in what constitutes a novel activity among Archaea. The holoenzyme was composed of two subunits of apparent molecular masses of 28 and 16 kDa. The larger subunit appeared to be glycosylated and was identical to DoxA, and the smaller was identical to DoxD. Both subunits had been described previously as a part of the terminal quinol:oxygen oxidoreductase complex (cytochrome aa3).

Original languageEnglish
Pages (from-to)1147-1160
Number of pages14
JournalMolecular Microbiology
Volume53
Issue number4
DOIs
Publication statusPublished - 1 Aug 2004

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Thiosulfates
Sulfur
Oxidoreductases
Oxygen
Membranes
Archaea
Acidianus
Sulfolobus
Hydroquinones
Dithionite
Vitamin K 2
Sulfites
Holoenzymes
Proteins
Electron Transport Complex IV
benzoquinone
Oxygen Consumption
Sulfates
Electrons
Enzymes

Cite this

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title = "Coupling of the pathway of sulphur oxidation to dioxygen reduction: Characterization of a novel membrane-bound thiosulphate:quinone oxidoreductase",
abstract = "Thiosulphate is one of the products of the initial step of the elemental sulphur oxidation pathway in the thermoacidophilic archaeon Acidianus ambivalens. A novel thiosulphate:quinone oxidoreductase (TQO) activity was found in the membrane extracts of aerobically grown cells of this organism. The enzyme was purified 21-fold from the solubilized membrane fraction. The TQO oxidized thiosulphate with tetrathionate as product and ferricyanide or decyl ubiquinone (DQ) as electron acceptors. The maximum specific activity with ferricyanide was 73.4 U (mg protein)-1 at 92°C and pH 6, with DQ it was 397 mU (mg protein)-1 at 80°C. The Km values were 2.6 mM for thiosulphate (kcat = 167 s-1), 3.4 mM for ferricyanide and 5.87 μM for DQ. The enzymic activity was inhibited by sulphite (Ki = 5 μM), metabisulphite, dithionite and TritonX-100, but not by sulphate or tetrathionate. A mixture of caldariella quinone, sulfolobus quinone and menaquinone was non-covalently bound to the protein. No other cofactors were detected. Oxygen consumption was measured in membrane fractions upon thiosulphate addition, thus linking thiosulphate oxidation to dioxygen reduction, in what constitutes a novel activity among Archaea. The holoenzyme was composed of two subunits of apparent molecular masses of 28 and 16 kDa. The larger subunit appeared to be glycosylated and was identical to DoxA, and the smaller was identical to DoxD. Both subunits had been described previously as a part of the terminal quinol:oxygen oxidoreductase complex (cytochrome aa3).",
author = "M{\"u}ller, {Fabian H.} and Bandeiras, {Tiago M.} and Tim Urich and Miguel Teixeira and Gomes, {Cl{\'a}udio M.} and Arnulf Kletzin",
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T1 - Coupling of the pathway of sulphur oxidation to dioxygen reduction

T2 - Characterization of a novel membrane-bound thiosulphate:quinone oxidoreductase

AU - Müller, Fabian H.

AU - Bandeiras, Tiago M.

AU - Urich, Tim

AU - Teixeira, Miguel

AU - Gomes, Cláudio M.

AU - Kletzin, Arnulf

PY - 2004/8/1

Y1 - 2004/8/1

N2 - Thiosulphate is one of the products of the initial step of the elemental sulphur oxidation pathway in the thermoacidophilic archaeon Acidianus ambivalens. A novel thiosulphate:quinone oxidoreductase (TQO) activity was found in the membrane extracts of aerobically grown cells of this organism. The enzyme was purified 21-fold from the solubilized membrane fraction. The TQO oxidized thiosulphate with tetrathionate as product and ferricyanide or decyl ubiquinone (DQ) as electron acceptors. The maximum specific activity with ferricyanide was 73.4 U (mg protein)-1 at 92°C and pH 6, with DQ it was 397 mU (mg protein)-1 at 80°C. The Km values were 2.6 mM for thiosulphate (kcat = 167 s-1), 3.4 mM for ferricyanide and 5.87 μM for DQ. The enzymic activity was inhibited by sulphite (Ki = 5 μM), metabisulphite, dithionite and TritonX-100, but not by sulphate or tetrathionate. A mixture of caldariella quinone, sulfolobus quinone and menaquinone was non-covalently bound to the protein. No other cofactors were detected. Oxygen consumption was measured in membrane fractions upon thiosulphate addition, thus linking thiosulphate oxidation to dioxygen reduction, in what constitutes a novel activity among Archaea. The holoenzyme was composed of two subunits of apparent molecular masses of 28 and 16 kDa. The larger subunit appeared to be glycosylated and was identical to DoxA, and the smaller was identical to DoxD. Both subunits had been described previously as a part of the terminal quinol:oxygen oxidoreductase complex (cytochrome aa3).

AB - Thiosulphate is one of the products of the initial step of the elemental sulphur oxidation pathway in the thermoacidophilic archaeon Acidianus ambivalens. A novel thiosulphate:quinone oxidoreductase (TQO) activity was found in the membrane extracts of aerobically grown cells of this organism. The enzyme was purified 21-fold from the solubilized membrane fraction. The TQO oxidized thiosulphate with tetrathionate as product and ferricyanide or decyl ubiquinone (DQ) as electron acceptors. The maximum specific activity with ferricyanide was 73.4 U (mg protein)-1 at 92°C and pH 6, with DQ it was 397 mU (mg protein)-1 at 80°C. The Km values were 2.6 mM for thiosulphate (kcat = 167 s-1), 3.4 mM for ferricyanide and 5.87 μM for DQ. The enzymic activity was inhibited by sulphite (Ki = 5 μM), metabisulphite, dithionite and TritonX-100, but not by sulphate or tetrathionate. A mixture of caldariella quinone, sulfolobus quinone and menaquinone was non-covalently bound to the protein. No other cofactors were detected. Oxygen consumption was measured in membrane fractions upon thiosulphate addition, thus linking thiosulphate oxidation to dioxygen reduction, in what constitutes a novel activity among Archaea. The holoenzyme was composed of two subunits of apparent molecular masses of 28 and 16 kDa. The larger subunit appeared to be glycosylated and was identical to DoxA, and the smaller was identical to DoxD. Both subunits had been described previously as a part of the terminal quinol:oxygen oxidoreductase complex (cytochrome aa3).

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U2 - 10.1111/j.1365-2958.2004.04193.x

DO - 10.1111/j.1365-2958.2004.04193.x

M3 - Article

VL - 53

SP - 1147

EP - 1160

JO - Molecular Microbiology

JF - Molecular Microbiology

SN - 0950-382X

IS - 4

ER -