ID   COX3_DICDI              Reviewed;         435 AA.
AC   O21049;
DT   04-DEC-2007, integrated into UniProtKB/Swiss-Prot.
DT   01-JAN-1998, sequence version 1.
DT   24-JAN-2024, entry version 115.
DE   RecName: Full=Cytochrome c oxidase subunit 3;
DE            EC=7.1.1.9;
DE   AltName: Full=Cytochrome c oxidase polypeptide III;
GN   Name=cox3; ORFNames=DDB_G0294092;
OS   Dictyostelium discoideum (Social amoeba).
OG   Mitochondrion.
OC   Eukaryota; Amoebozoa; Evosea; Eumycetozoa; Dictyostelia; Dictyosteliales;
OC   Dictyosteliaceae; Dictyostelium.
OX   NCBI_TaxID=44689;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=AX3;
RX   PubMed=9000384; DOI=10.1007/s002940050179;
RA   Ogawa S., Matsuo K., Angata K., Yanagisawa K., Tanaka Y.;
RT   "Group-I introns in the cytochrome c oxidase genes of Dictyostelium
RT   discoideum: two related ORFs in one loop of a group-I intron, a cox1/2
RT   hybrid gene and an unusually large cox3 gene.";
RL   Curr. Genet. 31:80-88(1997).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=AX3;
RX   PubMed=10821186; DOI=10.1007/pl00008685;
RA   Ogawa S., Yoshino R., Angata K., Iwamoto M., Pi M., Kuroe K., Matsuo K.,
RA   Morio T., Urushihara H., Yanagisawa K., Tanaka Y.;
RT   "The mitochondrial DNA of Dictyostelium discoideum: complete sequence, gene
RT   content and genome organization.";
RL   Mol. Gen. Genet. 263:514-519(2000).
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:P00420}.
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:P00420};
CC       PhysiologicalDirection=left-to-right; Xref=Rhea:RHEA:11437;
CC         Evidence={ECO:0000250|UniProtKB:P00420};
CC   -!- SUBUNIT: Component of the cytochrome c oxidase (complex IV, CIV), a
CC       multisubunit enzyme composed of a catalytic core of 3 subunits and
CC       several supernumerary subunits. The complex exists as a monomer or a
CC       dimer and forms supercomplexes (SCs) in the inner mitochondrial
CC       membrane with ubiquinol-cytochrome c oxidoreductase (cytochrome b-c1
CC       complex, complex III, CIII). {ECO:0000250|UniProtKB:P00420}.
CC   -!- SUBCELLULAR LOCATION: Mitochondrion inner membrane
CC       {ECO:0000250|UniProtKB:P00420}; Multi-pass membrane protein
CC       {ECO:0000250|UniProtKB:P00420}.
CC   -!- SIMILARITY: Belongs to the cytochrome c oxidase subunit 3 family.
CC       {ECO:0000305}.
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DR   EMBL; D16579; BAA21120.1; -; Genomic_DNA.
DR   EMBL; AB000109; BAA78053.1; -; Genomic_DNA.
DR   PIR; T43749; T43749.
DR   RefSeq; NP_050071.1; NC_000895.1.
DR   AlphaFoldDB; O21049; -.
DR   SMR; O21049; -.
DR   STRING; 44689.O21049; -.
DR   GeneID; 2193893; -.
DR   KEGG; ddi:DidioMp04; -.
DR   dictyBase; DDB_G0294092; cox3.
DR   InParanoid; O21049; -.
DR   PhylomeDB; O21049; -.
DR   PRO; PR:O21049; -.
DR   Proteomes; UP000002195; Mitochondrion.
DR   GO; GO:0005743; C:mitochondrial inner membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0004129; F:cytochrome-c oxidase activity; IEA:UniProtKB-EC.
DR   GO; GO:0006123; P:mitochondrial electron transport, cytochrome c to oxygen; IBA:GO_Central.
DR   CDD; cd01665; Cyt_c_Oxidase_III; 1.
DR   Gene3D; 1.20.120.80; Cytochrome c oxidase, subunit III, four-helix bundle; 2.
DR   InterPro; IPR024791; Cyt_c/ubiquinol_Oxase_su3.
DR   InterPro; IPR033945; Cyt_c_oxase_su3_dom.
DR   InterPro; IPR000298; Cyt_c_oxidase-like_su3.
DR   InterPro; IPR035973; Cyt_c_oxidase_su3-like_sf.
DR   InterPro; IPR013833; Cyt_c_oxidase_su3_a-hlx.
DR   PANTHER; PTHR11403:SF7; CYTOCHROME C OXIDASE SUBUNIT 3; 1.
DR   PANTHER; PTHR11403; CYTOCHROME C OXIDASE SUBUNIT III; 1.
DR   Pfam; PF00510; COX3; 2.
DR   SUPFAM; SSF81452; Cytochrome c oxidase subunit III-like; 2.
DR   PROSITE; PS50253; COX3; 1.
PE   3: Inferred from homology;
KW   Membrane; Mitochondrion; Mitochondrion inner membrane; Reference proteome;
KW   Translocase; Transmembrane; Transmembrane helix.
FT   CHAIN           1..435
FT                   /note="Cytochrome c oxidase subunit 3"
FT                   /id="PRO_0000312370"
FT   TRANSMEM        70..90
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        96..116
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        132..152
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        176..196
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        325..345
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        360..380
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        412..432
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
SQ   SEQUENCE   435 AA;  50234 MW;  5AC920869B67F434 CRC64;
     MKGFFENLFR QNVRSVINTG KKVGARAAAR EIINQEWGYP LANHEVLFLT NVYQPKHMKR
     HPFHIVRGTV APLAVTLPLG FFVLNYFGVI SSKLGLLIAL SSFIGGLVIW TISIIFDSLY
     DQQHTYEVKR GLVMGMMMFI ISEVMFFFSF FWSYFYISLS PNIAIGCVWP PYGLTVYSYM
     GLPLLNTVLL LLSGAILTDG YTILTEQKAV HEKNEKVLAV EEAFKNLMNL YKTKNSINTL
     TFVDERRDKF FGKESRQEDK IAEQKLIAIS AGVKELRDLD WDLYFFENPE NIEPNYKEPT
     NLSVIEYALI TIYLKKRNKV IKTRLYFTLL CAVVFLACQG YEYFFAPFSM NDGIYGSLFF
     LLTGFHGFHV LVGSILIGII TIRFIVGNFN LLNVGTNFQI YKNKSTGFAC TLFYWHFVDI
     VWIFLYIVIY WWGSR
//