The domain within your query sequence starts at position 3 and ends at position 129; the E-value for the COX5B domain shown below is 9.2e-53.

SRLLRGVGALAAQALRAHGPRGAAVTRSMASGGGVPTDEEQATGLEREIMIAAQKGLDPY
NMLPPKAASGTKEDPNLVPSISNKRIVGCICEEDNCTVIWFWLHKGESQRCPNCGTHYKL
VPHQMAH

COX5B

COX5B
PFAM accession number:PF01215
Interpro abstract (IPR002124):

Cytochrome c oxidase ( EC 1.9.3.1 ) 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 [ (PUBMED:6307356) ]. In eukaryotes this enzyme complex is located in the mitochondrial inner membrane; in aerobic prokaryotes it is found in the plasma membrane.

In eukaryotes, in addition to the three large subunits, I, II and III, that form the catalytic centre of the enzyme complex, there are a variable number of small polypeptidic subunits. One of these subunits, which is known as Vb in mammals, V in Dictyostelium discoideum (Slime mold) and IV in yeast, binds a zinc atom. The sequence of subunit Vb is well conserved and includes three conserved cysteines that coordinate the zinc ion [ (PUBMED:1661610) (PUBMED:8638158) ]. Two of these cysteines are clustered in the C-terminal section of the subunit.

GO component:mitochondrial envelope (GO:0005740)
GO function:cytochrome-c oxidase activity (GO:0004129)

This is a PFAM domain. For full annotation and more information, please see the PFAM entry COX5B