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Literature summary for 1.10.3.11 extracted from

  • Yap, L.L.; Lin, M.T.; Ouyang, H.; Samoilova, R.I.; Dikanov, S.A.; Gennis, R.B.
    The quinone-binding sites of the cytochrome bo3 ubiquinol oxidase from Escherichia coli (2010), Biochim. Biophys. Acta, 1797, 1924-1932.
    View publication on PubMedView publication on EuropePMC

Protein Variants

Protein Variants Comment Organism
D188A site-directed mutagenesis, the mutant shows altered sensitivity to inhibitor aurachin C1-10 compared to the wild-type enzyme, The mutant oxidase is not able to support aerobic growth when expressed in a strain of Escherichia coli without a genomically encoded respiratory oxidase Escherichia coli
D188N site-directed mutagenesis, the mutant shows altered sensitivity to inhibitor aurachin C1-10 compared to the wild-type enzyme Escherichia coli
D75E site-directed mutagenesis at the QH-site of cytochrome bo3, the mutant shows similar activity compared to the wild-type enzyme Escherichia coli
D75H site-directed mutagenesis at the QH-site of cytochrome bo3, the mutant shows highly reduced enzyme activity compared to the wild-type enzyme Escherichia coli
D75N site-directed mutagenesis at the QH-site of cytochrome bo3, the mutant shows highly reduced enzyme activity compared to the wild-type enzyme Escherichia coli
D75R site-directed mutagenesis at the QH-site of cytochrome bo3, the mutant shows highly reduced enzyme activity compared to the wild-type enzyme Escherichia coli
H98N site-directed mutagenesis at the QH-site of cytochrome bo3, the mutant shows highly reduced enzyme activity compared to the wild-type enzyme Escherichia coli
H98S site-directed mutagenesis at the QH-site of cytochrome bo3, the mutant shows highly reduced enzyme activity compared to the wild-type enzyme Escherichia coli
H98S site-directed mutagenesis, the mutant shows altered sensitivity to inhibitor aurachin C1-100 compared to the wild-type enzyme Escherichia coli
H98T site-directed mutagenesis at the QH-site of cytochrome bo3, the mutant shows highly reduced enzyme activity compared to the wild-type enzyme Escherichia coli
Q101N site-directed mutagenesis at the QH-site of cytochrome bo3, the mutant shows highly reduced enzyme activity compared to the wild-type enzyme Escherichia coli
R257Q site-directed mutagenesis, the mutant shows altered sensitivity to inhibitor aurachin C1-10 compared to the wild-type enzyme. The mutant oxidase is not able to support aerobic growth when expressed in a strain of Escherichia coli without a genomically encoded respiratory oxidase Escherichia coli
R71D site-directed mutagenesis at the QH-site of cytochrome bo3, the mutant shows highly reduced enzyme activity compared to the wild-type enzyme Escherichia coli
R71D/D75R site-directed mutagenesis at the QH-site of cytochrome bo3, the mutant shows highly reduced enzyme activity compared to the wild-type enzyme Escherichia coli
R71K site-directed mutagenesis at the QH-site of cytochrome bo3, the mutant shows highly reduced enzyme activity compared to the wild-type enzyme Escherichia coli
R71Q site-directed mutagenesis at the QH-site of cytochrome bo3, the mutant shows highly reduced enzyme activity compared to the wild-type enzyme Escherichia coli
WI36A site-directed mutagenesis, the mutant shows altered sensitivity to inhibitor aurachin C1-10 compared to the wild-type enzyme Escherichia coli

Inhibitors

Inhibitors Comment Organism Structure
2-heptyl-4-hydroxyquinoline N-oxide i.e. HQNO, binds stoichiometrically to the enzyme and prevents formation of the ubisemiquinone at the QH-site, but does not displace the ubiquinone-8 bound at the QH-site, enzyme binding kineticss, overview Escherichia coli
aurachin C1-10 prevents formation of the ubisemiquinone at the QH-site, but appears to compete for quinol binding at the QL-site, enzyme binding kineticss, overview Escherichia coli
additional information presence of high affinity inhibitors, 2-heptyl-4-hydroxyquinoline N-oxide and aurachin C1–10, does not displace ubiquinone-8 from the QH site Escherichia coli

Localization

Localization Comment Organism GeneOntology No. Textmining
membrane cytochrome bo3 is the major respiratory oxidase located in the cytoplasmic membrane of Escherichia coli when grown under high oxygen tension Escherichia coli 16020
-

Metals/Ions

Metals/Ions Comment Organism Structure
Fe2+ heme iron Escherichia coli

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
2 ubiquinol + O2 Escherichia coli
-
2 ubiquinone + 2 H2O
-
?

Organism

Organism UniProt Comment Textmining
Escherichia coli
-
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
2 ubiquinol + O2
-
Escherichia coli 2 ubiquinone + 2 H2O
-
?
2 ubiquinol-8 + O2 the quinone bound at the QH site can form a stable semiquinone. The tightly bound ubiquinone-8 at the QH site is not displaced by ubiquinol-1 even during enzyme turnover Escherichia coli 2 ubiquinone-8 + 2 H2O
-
?
additional information two assay methods: a coupled assay with rat liver DT-diaphorase and NADH as the reductant, and a direct assay using a oxygen electrode, overview Escherichia coli ?
-
?

Synonyms

Synonyms Comment Organism
cytochrome bo3
-
Escherichia coli
cytochrome bo3 ubiquinol oxidase
-
Escherichia coli

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
37
-
assay at Escherichia coli

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7
-
assay at Escherichia coli

Ki Value [mM]

Ki Value [mM] Ki Value maximum [mM] Inhibitor Comment Organism Structure
0.000015
-
aurachin C1-10 pH 7.0, 37°C, wild-type enzyme Escherichia coli
0.000074
-
2-heptyl-4-hydroxyquinoline N-oxide pH 7.0, 37°C, wild-type enzyme Escherichia coli

General Information

General Information Comment Organism
additional information analysis of a one-site Q-site model and a two-site Q-site model, overview Escherichia coli
physiological function cytochrome bo3 oxidase catalyzes the 2-electron oxidation of ubiquinol-8 and the 4-electron reduction of dioxygen to water Escherichia coli