ID   COX3_PROWI              Reviewed;         262 AA.
AC   Q37620;
DT   15-JUL-1998, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   22-FEB-2023, entry version 92.
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   Prototheca wickerhamii.
OG   Mitochondrion.
OC   Eukaryota; Viridiplantae; Chlorophyta; core chlorophytes; Trebouxiophyceae;
OC   Chlorellales; Chlorellaceae; Prototheca.
OX   NCBI_TaxID=3111;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=263-11;
RX   PubMed=8133522; DOI=10.1006/jmbi.1994.1210;
RA   Wolff G., Plante I., Lang B.F., Kueck U., Burger G.;
RT   "Complete sequence of the mitochondrial DNA of the chlorophyte alga
RT   Prototheca wickerhamii. Gene content and genome organization.";
RL   J. Mol. Biol. 237:75-86(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; U02970; AAD12641.1; -; Genomic_DNA.
DR   PIR; T11922; T11922.
DR   RefSeq; NP_042253.1; NC_001613.1.
DR   AlphaFoldDB; Q37620; -.
DR   SMR; Q37620; -.
DR   GeneID; 802127; -.
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; 1.
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..262
FT                   /note="Cytochrome c oxidase subunit 3"
FT                   /id="PRO_0000183839"
FT   TRANSMEM        13..33
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        38..58
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        82..102
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        134..154
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        159..179
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        200..220
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        237..257
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
SQ   SEQUENCE   262 AA;  29600 MW;  F4CC81AB17C2850E CRC64;
     MRKHPFHLVD PSPWPLLASF AAFLSTTGGV MYMHAYSGGG LLLAIGQLSL FYVMYVWWRD
     VIREGTYQGH HTNPVQVGLR YGMLLFILSE IMFFFAFFWA FFHSSLAPTI EIGAVWPPKG
     IQVLNPWEIP FLNTIILLTS GASVTWAHHA ILAGNRKQGI ISLAITVLLA VIFTGFQALE
     YLEAPFTISD GIYGSTFYLA TGFHGFHVII GTIFIAVCLF RLVLHHFSKS HHLGFEAAAW
     YWHMVDVVWL FLFVCIYYWG GA
//