Literature summary for 7.1.1.4 extracted from

Komorowski, L.; Verheyen, W.; Sch�fer, G.
The archaeal respiratory supercomplex SoxM from Sulfolobus acidocaldarius combines features of quinole and cytochrome c oxidases (2002), Biol. Chem., 383, 1791-1799.

Search for more literature for 7.1.1.4

Inhibitors

Inhibitors	Comment	Organism	Structure
2-decylchinolone	pI50: 4.9	Sulfolobus acidocaldarius
2-dodecyl-N-hydroxychinolone	pI50: 5.9	Sulfolobus acidocaldarius
2-methyl-3-dodecyl-N-hydroxy-chinolone	pI50: 7.3	Sulfolobus acidocaldarius
2-methyl-3-dodecylchinolone	pI50: 6.2	Sulfolobus acidocaldarius
3-methyl-2-decylchinolone	pI50: 5.5	Sulfolobus acidocaldarius
cyanide	-	Sulfolobus acidocaldarius
EDTA	causes maximal inhibition of either the isolated enzyme, or the activity of the crude membrane extract by 63% with a half-maximal effect at 21 mM	Sulfolobus acidocaldarius
additional information	benzoquinone, naphthoquinone and phenol derivatives do not influence the reactivity	Sulfolobus acidocaldarius
phosphate	inhibitory effect which at the pH-optimum and 50 mM phosphate concentration amounts to about 35%	Sulfolobus acidocaldarius

KM Value [mM]

KM Value [mM]	KM Value Maximum [mM]	Substrate	Comment	Organism	Structure
0.036	-	caldariellaquinol	pH 4.5, 50°C	Sulfolobus acidocaldarius
0.057	-	ferrocytochrome c	pH 4.5, 50°C	Sulfolobus acidocaldarius

Metals/Ions

Metals/Ions	Comment	Organism	Structure
Cu	the enzyme contains a total of seven metal redox centers. One of it, the blue copper protein sulfocyanin, functionally links two subcomplexes. One is a bb3-type terminal oxidase moiety containing CuA and CuB, whereas the other consists of a Rieske FeS-protein and a homolog to cytochrome b in this case hosting two hemes AS. Based on a 1:1 stoichiometry, 1 mol complex contains 6 mol Fe and 4 mol Cu	Sulfolobus acidocaldarius
Fe	the enzyme contains a total of seven metal redox centers. One of it, the blue copper protein sulfocyanin, functionally links two subcomplexes. One is a bb3-type terminal oxidase moiety containing CuA and CuB, whereas the other consists of a Rieske FeS-protein and a homolog to cytochrome b in this case hosting two hemes AS. Based on a 1:1 stoichiometry, 1 mol complex contains 6 mol Fe and 4 mol Cu	Sulfolobus acidocaldarius

Molecular Weight [Da]

Molecular Weight [Da]	Molecular Weight Maximum [Da]	Comment	Organism
224000	-	gel filtration	Sulfolobus acidocaldarius

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
caldariellaquinol + O2 + n H+/in	Sulfolobus acidocaldarius	function as a redox-driven proton pump, within the SoxGFE assembly of the supercomplex acting as a caldariella-quinol:sulfocyanin oxidoreductase	caldariellaquinone + H2O + n H+/out	-	?

Organism

Organism	UniProt	Comment	Textmining
Sulfolobus acidocaldarius	P39481 and Q97UN3 and Q53765 and Q53766 and Q59825 and Q53768	P39481 (soxM), Q97UN3 (soxG), Q53765 (soxE), Q53766 (soxD), Q59825 (soxH), Q53768 (soxI)	-

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
4 ferrocytochrome c + O2 + 4 H+	enzymatic activity is monitored with reduced cytochrome c despite not being the natural substrate. Sulfolobus acidocaldarius does not contain any c-type cytochrome. However, it can be used for in vitro assays of the terminal oxidase moiety in the complex because electrons can be accepted form either sulfocyanin (SoxE) or from SoxH. SoxABCD does not react with cytochrome c. The tested activity is specific for the SoxM complex	Sulfolobus acidocaldarius	4 ferricytochrome c + 2 H2O	-	?
caldariellaquinol + O2 + n H+/in	function as a redox-driven proton pump, within the SoxGFE assembly of the supercomplex acting as a caldariella-quinol:sulfocyanin oxidoreductase	Sulfolobus acidocaldarius	caldariellaquinone + H2O + n H+/out	-	?
caldariellaquinol + O2 + n H+/in	the SoxM-complex can oxidize the electron donor horseheart cytochrome c as well as caldariellaquinol. Based on genetic information it is suggested that the complex provides two proton pumping sites. However a preparation of liposomes with tetraether lipids together with the complex is not sufficient to perform proton pumping experiments	Sulfolobus acidocaldarius	caldariellaquinone + H2O + n H+/out	-	?

Subunits

Subunits	Comment	Organism
More	6 polypeptide subunits: SoxM (87000 Da), SoxG (56000 Da), SoxE (21000 Da) , SoxF (26800 Da), SoxH (16300 Da), SoxI (16800 Da). Proposed structural organization of the supercomplex: therein the polypeptides SoxG, SoxF, and SoxE represent an assembly. Sulfocyanin (SoxE) has a typical membrane spanning N-terminal anchor sequence fixing it firmly to the complex	Sulfolobus acidocaldarius

Synonyms

Synonyms	Comment	Organism
SoxM supercomplex	-	Sulfolobus acidocaldarius

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
50	-	assay at	Sulfolobus acidocaldarius

pH Optimum

pH Optimum Minimum	pH Optimum Maximum	Comment	Organism
4.5	-	assay at	Sulfolobus acidocaldarius
5.3	-	-	Sulfolobus acidocaldarius

Cofactor

Cofactor	Comment	Organism	Structure
heme	the enzyme contains 2 heme As and 2 heme B (b and b3)	Sulfolobus acidocaldarius

General Information

General Information	Comment	Organism
physiological function	the enzyme may be involved in the electron pathway, it may be involved in regulatory adaptation to environmental stress	Sulfolobus acidocaldarius

Use of this online version of BRENDA is free under the CC BY 4.0 license. See terms of use for full details.

Release 2023.1 (January 2023)