ID   COX2_LEPOC              Reviewed;          72 AA.
AC   P29659;
DT   01-APR-1993, integrated into UniProtKB/Swiss-Prot.
DT   01-APR-1993, sequence version 1.
DT   28-JUN-2023, entry version 106.
DE   RecName: Full=Cytochrome c oxidase subunit 2;
DE            EC=7.1.1.9;
DE   AltName: Full=Cytochrome c oxidase polypeptide II;
DE   Flags: Fragment;
GN   Name=mt-co2; Synonyms=coii, coxii, mtco2;
OS   Lepisosteus oculatus (Spotted gar).
OG   Mitochondrion.
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi;
OC   Actinopterygii; Neopterygii; Holostei; Semionotiformes; Lepisosteidae;
OC   Lepisosteus.
OX   NCBI_TaxID=7918;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=1663569; DOI=10.1093/oxfordjournals.molbev.a040685;
RA   Normark B.B., McCune A.R., Harrison R.G.;
RT   "Phylogenetic relationships of neopterygian fishes, inferred from
RT   mitochondrial DNA sequences.";
RL   Mol. Biol. Evol. 8:819-834(1991).
CC   -!- FUNCTION: Component of the cytochrome c oxidase, the last enzyme in the
CC       mitochondrial electron transport chain which drives oxidative
CC       phosphorylation. The respiratory chain contains 3 multisubunit
CC       complexes succinate dehydrogenase (complex II, CII), ubiquinol-
CC       cytochrome c oxidoreductase (cytochrome b-c1 complex, complex III,
CC       CIII) and cytochrome c oxidase (complex IV, CIV), that cooperate to
CC       transfer electrons derived from NADH and succinate to molecular oxygen,
CC       creating an electrochemical gradient over the inner membrane that
CC       drives transmembrane transport and the ATP synthase. Cytochrome c
CC       oxidase is the component of the respiratory chain that catalyzes the
CC       reduction of oxygen to water. Electrons originating from reduced
CC       cytochrome c in the intermembrane space (IMS) are transferred via the
CC       dinuclear copper A center (CU(A)) of subunit 2 and heme A of subunit 1
CC       to the active site in subunit 1, a binuclear center (BNC) formed by
CC       heme A3 and copper B (CU(B)). The BNC reduces molecular oxygen to 2
CC       water molecules using 4 electrons from cytochrome c in the IMS and 4
CC       protons from the mitochondrial matrix. {ECO:0000250|UniProtKB:P00410}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=4 Fe(II)-[cytochrome c] + 8 H(+)(in) + O2 = 4 Fe(III)-
CC         [cytochrome c] + 4 H(+)(out) + 2 H2O; Xref=Rhea:RHEA:11436,
CC         Rhea:RHEA-COMP:10350, Rhea:RHEA-COMP:14399, ChEBI:CHEBI:15377,
CC         ChEBI:CHEBI:15378, ChEBI:CHEBI:15379, ChEBI:CHEBI:29033,
CC         ChEBI:CHEBI:29034; EC=7.1.1.9;
CC         Evidence={ECO:0000250|UniProtKB:P00410};
CC       PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:11437;
CC         Evidence={ECO:0000250|UniProtKB:P00410};
CC   -!- COFACTOR:
CC       Name=Cu cation; Xref=ChEBI:CHEBI:23378;
CC         Evidence={ECO:0000250|UniProtKB:P68530};
CC       Note=Binds a dinuclear copper A center per subunit.
CC       {ECO:0000250|UniProtKB:P68530};
CC   -!- SUBUNIT: Component of the cytochrome c oxidase (complex IV, CIV), a
CC       multisubunit enzyme composed of 14 subunits. The complex is composed of
CC       a catalytic core of 3 subunits MT-CO1, MT-CO2 and MT-CO3, encoded in
CC       the mitochondrial DNA, and 11 supernumerary subunits COX4I, COX5A,
CC       COX5B, COX6A, COX6B, COX6C, COX7A, COX7B, COX7C, COX8 and NDUFA4, which
CC       are encoded in the nuclear genome. The complex exists as a monomer or a
CC       dimer and forms supercomplexes (SCs) in the inner mitochondrial
CC       membrane with NADH-ubiquinone oxidoreductase (complex I, CI) and
CC       ubiquinol-cytochrome c oxidoreductase (cytochrome b-c1 complex, complex
CC       III, CIII), resulting in different assemblies (supercomplex
CC       SCI(1)III(2)IV(1) and megacomplex MCI(2)III(2)IV(2)) (By similarity).
CC       Found in a complex with TMEM177, COA6, COX18, COX20, SCO1 and SCO2.
CC       Interacts with TMEM177 in a COX20-dependent manner. Interacts with
CC       COX20. Interacts with COX16 (By similarity).
CC       {ECO:0000250|UniProtKB:P00403, ECO:0000250|UniProtKB:P68530}.
CC   -!- SUBCELLULAR LOCATION: Mitochondrion inner membrane
CC       {ECO:0000250|UniProtKB:P68530}; Multi-pass membrane protein
CC       {ECO:0000250|UniProtKB:P68530}.
CC   -!- SIMILARITY: Belongs to the cytochrome c oxidase subunit 2 family.
CC       {ECO:0000305}.
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DR   EMBL; M64898; AAB01464.1; -; Genomic_DNA.
DR   EMBL; M64901; AAB01467.1; -; Genomic_DNA.
DR   AlphaFoldDB; P29659; -.
DR   SMR; P29659; -.
DR   STRING; 7918.ENSLOCP00000022474; -.
DR   eggNOG; KOG4767; Eukaryota.
DR   HOGENOM; CLU_036876_2_3_1; -.
DR   InParanoid; P29659; -.
DR   Proteomes; UP000018468; Unplaced.
DR   GO; GO:0005743; C:mitochondrial inner membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0045277; C:respiratory chain complex IV; ISS:UniProtKB.
DR   GO; GO:0004129; F:cytochrome-c oxidase activity; IEA:UniProtKB-EC.
DR   Gene3D; 1.10.287.90; -; 1.
DR   InterPro; IPR045187; CcO_II.
DR   InterPro; IPR011759; Cyt_c_oxidase_su2_TM_dom.
DR   InterPro; IPR036257; Cyt_c_oxidase_su2_TM_sf.
DR   PANTHER; PTHR22888:SF9; CYTOCHROME C OXIDASE SUBUNIT 2; 1.
DR   PANTHER; PTHR22888; CYTOCHROME C OXIDASE, SUBUNIT II; 1.
DR   Pfam; PF02790; COX2_TM; 1.
DR   SUPFAM; SSF81464; Cytochrome c oxidase subunit II-like, transmembrane region; 1.
DR   PROSITE; PS50999; COX2_TM; 1.
PE   3: Inferred from homology;
KW   Copper; Electron transport; Membrane; Mitochondrion;
KW   Mitochondrion inner membrane; Reference proteome; Respiratory chain;
KW   Translocase; Transmembrane; Transmembrane helix; Transport.
FT   CHAIN           1..>72
FT                   /note="Cytochrome c oxidase subunit 2"
FT                   /id="PRO_0000183619"
FT   TOPO_DOM        1..14
FT                   /note="Mitochondrial intermembrane"
FT                   /evidence="ECO:0000250|UniProtKB:P68530"
FT   TRANSMEM        15..45
FT                   /note="Helical; Name=I"
FT                   /evidence="ECO:0000250|UniProtKB:P68530"
FT   TOPO_DOM        46..>72
FT                   /note="Mitochondrial matrix"
FT                   /evidence="ECO:0000250|UniProtKB:P68530"
FT   NON_TER         72
SQ   SEQUENCE   72 AA;  8081 MW;  AABC3332F740FA32 CRC64;
     MAHPSQLGFQ DAASPVMEEL LHFHDHALMI VFLISTLVLY IIVAMVSTKL TNKHILDSQE
     VEIVWTILPA VI
//