Q9XP88 · CYB_SMIAR

Function

function

Component of the ubiquinol-cytochrome c reductase complex (complex III or cytochrome b-c1 complex) that is part of the mitochondrial respiratory chain. The b-c1 complex mediates electron transfer from ubiquinol to cytochrome c. Contributes to the generation of a proton gradient across the mitochondrial membrane that is then used for ATP synthesis.

Miscellaneous

Heme 1 (or BL or b562) is low-potential and absorbs at about 562 nm, and heme 2 (or BH or b566) is high-potential and absorbs at about 566 nm.

Caution

The full-length protein contains only eight transmembrane helices, not nine as predicted by bioinformatics tools.

Cofactor

heme b (UniProtKB | Rhea| CHEBI:60344 )

Note: Binds 2 heme b groups non-covalently.

Features

Showing features for binding site.

138150100150200250300350
TypeIDPosition(s)Description
Binding site83Fe (UniProtKB | ChEBI) of heme b b562 (UniProtKB | ChEBI); axial binding residue
Binding site97Fe (UniProtKB | ChEBI) of heme b b566 (UniProtKB | ChEBI); axial binding residue
Binding site182Fe (UniProtKB | ChEBI) of heme b b562 (UniProtKB | ChEBI); axial binding residue
Binding site196Fe (UniProtKB | ChEBI) of heme b b566 (UniProtKB | ChEBI); axial binding residue
Binding site201a ubiquinone (UniProtKB | ChEBI)

GO annotations

AspectTerm
Cellular Componentmitochondrial inner membrane
Cellular Componentrespiratory chain complex III
Molecular Functionmetal ion binding
Molecular Functionubiquinol-cytochrome-c reductase activity
Biological Processmitochondrial electron transport, ubiquinol to cytochrome c

Keywords

Names & Taxonomy

Protein names

  • Recommended name
    Cytochrome b
  • Alternative names
    • Complex III subunit 3
    • Complex III subunit III
    • Cytochrome b-c1 complex subunit 3
    • Ubiquinol-cytochrome-c reductase complex cytochrome b subunit

Gene names

    • Name
      MT-CYB
    • Synonyms
      COB, CYTB, MTCYB

Encoded on

  • Mitochondrion

Organism names

Accessions

  • Primary accession
    Q9XP88

Subcellular Location

Features

Showing features for transmembrane.

TypeIDPosition(s)Description
Transmembrane33-53Helical
Transmembrane77-98Helical
Transmembrane113-133Helical
Transmembrane178-198Helical
Transmembrane226-246Helical
Transmembrane288-308Helical
Transmembrane320-340Helical
Transmembrane347-367Helical

Keywords

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00000615411-381Cytochrome b

Interaction

Subunit

The cytochrome bc1 complex contains 11 subunits: 3 respiratory subunits (MT-CYB, CYC1 and UQCRFS1), 2 core proteins (UQCRC1 and UQCRC2) and 6 low-molecular weight proteins (UQCRH/QCR6, UQCRB/QCR7, UQCRQ/QCR8, UQCR10/QCR9, UQCR11/QCR10 and a cleavage product of UQCRFS1). This cytochrome bc1 complex then forms a dimer.

Structure

Family & Domains

Sequence similarities

Belongs to the cytochrome b family.

Keywords

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    381
  • Mass (Da)
    42,771
  • Last updated
    1999-11-01 v1
  • Checksum
    B0F836D490D95F99
MINLRKTHPLMKIINHSFIDLPAPSNISAWWNFGSLLGVCLVIQILTGLFLAMHYTSDTLTAFSSVAHICRDVNYGWLIRNLHANGASMFFMCLFLHVGRGIYYGSYLYKETWNIGVILLLTVMATAFVGYVLPWGQMSFWGATVITNLLSAIPYIGTTLAEWIWGGFAVDKATLTRFFAFHFILPFIIMALVMVHLLFLHETGSNNPSGINPDSDKIPFHPYYTIKDALGLMILLLVLLSLALFSPDSLGDPDNFSPANPLNTPPHIKPEWYFLFAYAILRSIPNKLGGVLALLASILILLIIPLLHTANQRSMMFRPVSQTLFWILTANLITLTWIGGQPVEQPFIIIGQLASILYFTLILVLMPLAGMFENYMLEPKR

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AF088920
EMBL· GenBank· DDBJ
AAD38430.1
EMBL· GenBank· DDBJ
Genomic DNA

Similar Proteins

Disclaimer

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