COX3_HELAN
ID COX3_HELAN Reviewed; 265 AA.
AC P32808;
DT 01-OCT-1993, integrated into UniProtKB/Swiss-Prot.
DT 01-OCT-1993, sequence version 1.
DT 25-MAY-2022, entry version 96.
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; Synonyms=COXIII;
OS Helianthus annuus (Common sunflower).
OG Mitochondrion.
OC Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC asterids; campanulids; Asterales; Asteraceae; Asteroideae;
OC Heliantheae alliance; Heliantheae; Helianthus.
OX NCBI_TaxID=4232;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC STRAIN=cv. Gloriasol;
RX PubMed=2174745; DOI=10.1007/bf00318217;
RA Quagliariello C., Saiardi A., Gallerani R.;
RT "The cytochrome oxidase subunit III gene in sunflower mitochondria is
RT cotranscribed with an open reading frame conserved in higher plants.";
RL Curr. Genet. 18:355-363(1990).
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; X57669; CAA40865.1; -; Genomic_DNA.
DR PIR; S14123; S14123.
DR AlphaFoldDB; P32808; -.
DR SMR; P32808; -.
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 CDD; cd01665; Cyt_c_Oxidase_III; 1.
DR Gene3D; 1.20.120.80; -; 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; 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..265
FT /note="Cytochrome c oxidase subunit 3"
FT /id="PRO_0000183790"
FT TRANSMEM 16..36
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 41..61
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 81..101
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 162..182
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 200..220
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TRANSMEM 245..265
FT /note="Helical"
FT /evidence="ECO:0000255"
SQ SEQUENCE 265 AA; 29423 MW; BE30F0236E86C9EE CRC64;
MIESQRHSYH LVDPSPWPIS GSLGALATTV GGVMYMHSFQ GGATLLSLGL IFILYTMFVW
WRDVLRESTL EGHHTKVVQL GPRYGFILFI VSEVMFLFAL FRASSHSSLA PTVEIGGIWP
PKGIAVLDPR EIPFLNTPIP LSSGAAVTWA HHAILAGKEK RAVYALVATV SLALVFTAFQ
GMEYYQAPST ISDSIYGSTF FLATGFHGFH VIIGTLFSIV CGIRQYLGHL TKEHHVGFEA
AAWYWHFVDV VRLFPFVSIY WWGGI
