Cytochrome c oxidase (EC 18.104.22.168)  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.
January 2008 / Text revised; profile added.
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