ID   COX3_ACACA              Reviewed;         329 AA.
AC   Q37374;
DT   15-JUL-1998, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   22-FEB-2023, entry version 98.
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;
OS   Acanthamoeba castellanii (Amoeba).
OG   Mitochondrion.
OC   Eukaryota; Amoebozoa; Discosea; Longamoebia; Centramoebida;
OC   Acanthamoebidae; Acanthamoeba.
OX   NCBI_TaxID=5755;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=ATCC 30010 / Neff;
RX   PubMed=7844823; DOI=10.1006/jmbi.1994.0043;
RA   Burger G., Plante I., Lonergan K.M., Gray M.W.;
RT   "The mitochondrial DNA of the amoeboid protozoon, Acanthamoeba castellanii:
RT   complete sequence, gene content and genome organization.";
RL   J. Mol. Biol. 245:522-537(1995).
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; U12386; AAD11825.1; -; Genomic_DNA.
DR   PIR; S53833; S53833.
DR   RefSeq; NP_042532.1; NC_001637.1.
DR   AlphaFoldDB; Q37374; -.
DR   SMR; Q37374; -.
DR   GeneID; 1734027; -.
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:0019646; P:aerobic electron transport chain; IEA:InterPro.
DR   CDD; cd01665; Cyt_c_Oxidase_III; 1.
DR   Gene3D; 1.10.287.70; -; 1.
DR   Gene3D; 1.20.120.80; Cytochrome c oxidase, subunit III, four-helix bundle; 1.
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; 1.
DR   PROSITE; PS50253; COX3; 1.
PE   3: Inferred from homology;
KW   Membrane; Mitochondrion; Mitochondrion inner membrane; Translocase;
KW   Transmembrane; Transmembrane helix.
FT   CHAIN           1..329
FT                   /note="Cytochrome c oxidase subunit 3"
FT                   /id="PRO_0000183726"
FT   TRANSMEM        53..73
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        77..97
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        122..142
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        169..191
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        217..237
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        269..289
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        298..318
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
SQ   SEQUENCE   329 AA;  38914 MW;  A6F2036F57EE8047 CRC64;
     MKLNYDFFLN KFNNVYNNDI RLVDLSNKWW YHNCRVHFAG NQKHSFHIVT RSPWPLYSSI
     AALMFTFGLV MHMHNYFYGN LLSLAGFFLI LLMMFVWWRD VIRESTFSGY HTKKVQQGLR
     LGVILFIISE VMFFFSFFWA FFHASLSPSV VLGSVWPPLG INVLNPLKIP LLNTLILLLS
     GLTVTWSHHV IRDKSWQKFF FSNSNNEEFK APLLDNYVIC AFALFLTVFL GLEFTVWQGY
     EYYKASFYIY DGVYGSTFYM TTGLHGLHVI IGTLFLIVCF FRLIDLHFIY NHHFGYEAAI
     WYWHFVDVVW IFLFLSIYCW GSGVDSFFK
//