PROSITE documentation PDOC00663
Cytochrome c oxidase subunit Vb family signature and profile


Cytochrome c oxidase (EC [1] is an oligomeric enzymatic complex which is a component of the respiratory chain complex and is involved in the transfer of electrons from cytochrome c to oxygen. In eukaryotes this enzyme complex is located in the mitochondrial inner membrane; in aerobic prokaryotes it is found in the plasma membrane. In addition to the three large subunits that form the catalytic center of the enzyme complex there are, in eukaryotes, a variable number of small polypeptidic subunits. One of these subunits which is known as Vb in mammals, V in slime mold and IV in yeast, binds a zinc atom. The sequence of subunit Vb is well conserved and includes three to four conserved cysteines that coordinate the zinc ion [2,3]. Two of these cysteines are clustered in the C-terminal section of the subunit; we have used this region as a signature pattern. We also developed a profile that covers the whole subunit Vb zinc binding region.

Last update:

January 2008 / Text revised; profile added.


Technical section

PROSITE methods (with tools and information) covered by this documentation:

COX5B_2, PS51359; Cytochrome c oxidase subunit Vb, zinc binding domain profile  (MATRIX)

COX5B_1, PS00848; Cytochrome c oxidase subunit Vb, zinc binding region signature  (PATTERN)


1AuthorsCapaldi R.A. Malatesta F. Darley-Usmar V.M.
TitleStructure of cytochrome c oxidase.
SourceBiochim. Biophys. Acta 726:135-148(1983).
PubMed ID6307356

2AuthorsRizzuto R. Sandona D. Brini M. Capaldi R.A. Bisson R.
TitleThe most conserved nuclear-encoded polypeptide of cytochrome c oxidase is the putative zinc-binding subunit: primary structure of subunit V from the slime mold Dictyostelium discoideum.
SourceBiochim. Biophys. Acta 1129:100-104(1991).
PubMed ID1661610

3AuthorsTsukihara T. Aoyama H. Yamashita E. Tomizaki T. Yamaguchi H. Shinzawa-Itoh K. Nakashima R. Yaono R. Yoshikawa S.
TitleThe whole structure of the 13-subunit oxidized cytochrome c oxidase at 2.8 A.
SourceScience 272:1136-1144(1996).
PubMed ID8638158

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