H
IPR036927

Cytochrome c oxidase-like, subunit I superfamily

InterPro entry
Short nameCyt_c_oxase-like_su1_sf
Overlapping entries
 

Description

Cytochrome c oxidase (
7.1.1.9
) is a key enzyme in aerobic metabolism. Proton pumping haem-copper oxidases represent the terminal, energy-transfer enzymes of respiratory chains in prokaryotes and eukaryotes. The CuB-haem a3 (or haem o) binuclear centre, associated with the largest subunit I of cytochrome c and ubiquinol oxidases (
1.10.3.11
), is directly involved in the coupling between dioxygen reduction and proton pumping
[5, 1]
. Some terminal oxidases generate a transmembrane proton gradient across the plasma membrane (prokaryotes) or the mitochondrial inner membrane (eukaryotes).

The enzyme complex consists of 3-4 subunits (prokaryotes) up to 13 polypeptides (mammals) of which only the catalytic subunit (equivalent to mammalian subunit I (CO I) is found in all haem-copper respiratory oxidases. The presence of a bimetallic centre (formed by a high-spin haem and copper B) as well as a low-spin haem, both ligated to six conserved histidine residues near the outer side of four transmembrane spans within CO I is common to all family members
[2, 3, 4]
. In contrast to eukaryotes the respiratory chain of prokaryotes is branched to multiple terminal oxidases. The enzyme complexes vary in haem and copper composition, substrate type and substrate affinity. The different respiratory oxidases allow the cells to customize their respiratory systems according to a variety of environmental growth conditions
[5]
.

This entry represents a structural domain superfamily found in subunit I of cytochrome c oxidase as well as related proteins, including quinol oxidase. Structurally, it is composed of twelve transmembrane helices in an approximate threefold rotational symmetric arrangement.

References

1.The proton pump of heme-copper oxidases. Papa S, Capitanio N, Glaser P, Villani G. Cell Biol. Int. 18, 345-55, (1994). View articlePMID: 8049679

2.Evolution of cytochrome oxidase, an enzyme older than atmospheric oxygen. Castresana J, Lubben M, Saraste M, Higgins DG. EMBO J. 13, 2516-25, (1994). View articlePMID: 8013452

3.Structure of cytochrome c oxidase. Capaldi RA, Malatesta F, Darley-Usmar VM. Biochim. Biophys. Acta 726, 135-48, (1983). View articlePMID: 6307356

4.Structural models of the redox centres in cytochrome oxidase. Holm L, Saraste M, Wikstrom M. EMBO J. 6, 2819-23, (1987). View articlePMID: 2824194

5.The superfamily of heme-copper respiratory oxidases. Garcia-Horsman JA, Barquera B, Rumbley J, Ma J, Gennis RB. J. Bacteriol. 176, 5587-600, (1994). View articlePMID: 8083153

Cross References

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