ID   COX3_TRYBO              Reviewed;         286 AA.
AC   Q37355;
DT   01-NOV-1997, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   25-MAY-2022, entry version 85.
DE   RecName: Full=Cytochrome c oxidase subunit 3;
DE            EC=7.1.1.9;
DE   AltName: Full=Cytochrome c oxidase polypeptide III;
GN   Name=COIII;
OS   Trypanoplasma borreli.
OG   Mitochondrion.
OC   Eukaryota; Discoba; Euglenozoa; Kinetoplastea; Metakinetoplastina;
OC   Parabodonida; Trypanoplasma.
OX   NCBI_TaxID=5710;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=PG-JH;
RX   PubMed=7969154; DOI=10.1128/mcb.14.12.8174-8182.1994;
RA   Maslov D.A., Simpson L.;
RT   "RNA editing and mitochondrial genomic organization in the cryptobiid
RT   kinetoplastid protozoan Trypanoplasma borreli.";
RL   Mol. Cell. Biol. 14:8174-8182(1994).
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; U14181; AAA65016.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q37355; -.
DR   SMR; Q37355; -.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
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   Gene3D; 1.20.120.80; -; 1.
DR   InterPro; IPR024791; Cyt_c/ubiquinol_Oxase_su3.
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; PTHR11403; 1.
DR   Pfam; PF00510; COX3; 1.
DR   SUPFAM; SSF81452; SSF81452; 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..286
FT                   /note="Cytochrome c oxidase subunit 3"
FT                   /id="PRO_0000183869"
FT   TRANSMEM        13..33
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        40..60
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        85..105
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        133..153
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        173..195
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        199..221
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        223..243
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        253..273
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
SQ   SEQUENCE   286 AA;  33313 MW;  80C9A05526773808 CRC64;
     MYLFRIISLN LSGVFLFLSY TPLYITYLLG VVISSMMLTV GTFAITLDII LCILVVCFLI
     TTLLVIDSVL DSIRGLNSVG VLVRIIQYCF LWFVFSEFML FVVFFYTLYS ECLLINVEFT
     NIGCPVTTKY SNIILDLGYI FYWFLFDFFN IILNTVYLFI SGLCCNNVLS SILCREYLLS
     KIILGSSIFL GLLFIWNQVW EFNILIITLS VNIFCTILFS IDTLHFMHVL VGIVFMIISI
     FNIQSKKIGD IRIVLIVCII FYWHFVDIVW FFLLRFIYLD TLMVLK