Q9MLD7 · CYB_SINKE

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.

TypeIDPosition(s)Description
Binding site75Fe (UniProtKB | ChEBI) of heme b b562 (UniProtKB | ChEBI); axial binding residue
Binding site89Fe (UniProtKB | ChEBI) of heme b b566 (UniProtKB | ChEBI); axial binding residue
Binding site174Fe (UniProtKB | ChEBI) of heme b b562 (UniProtKB | ChEBI); axial binding residue
Binding site188Fe (UniProtKB | ChEBI) of heme b b566 (UniProtKB | ChEBI); axial binding residue
Binding site193a 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
    Q9MLD7

Subcellular Location

Features

Showing features for transmembrane.

TypeIDPosition(s)Description
Transmembrane25-45Helical
Transmembrane69-90Helical
Transmembrane105-125Helical
Transmembrane170-190Helical
Transmembrane218-238Helical
Transmembrane280-300Helical
Transmembrane312-332Helical
Transmembrane339-358Helical

Keywords

PTM/Processing

Features

Showing features for chain.

TypeIDPosition(s)Description
ChainPRO_00000607081-371Cytochrome b

Interaction

Subunit

The cytochrome bc1 complex contains 3 respiratory subunits (MT-CYB, CYC1 and UQCRFS1), 2 core proteins (UQCRC1 and UQCRC2) and probably 6 low-molecular weight proteins.

Structure

Family & Domains

Sequence similarities

Belongs to the cytochrome b family.

Keywords

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    371
  • Mass (Da)
    42,188
  • Last updated
    2000-10-01 v1
  • Checksum
    B6723C71E03BD70F
MSNQHTLLISNLLPVGSNISTWWNFGSMLLTCLILQITTGFFLAIHYTANINLAFSSVTHIMRDVPYGWIMQNLHAIGASMFFICIYIHIARGLYYGLYMNKNVWLSGTTLLITLMATAFFGYVLPWGQMSFWAATVITNLLTAIPYLGTTITTWLWGGFSINDPTLTRFFALHFILPFAIISLSSIHIILLHNKGSNNPLGTNSDIDKIPFHPYHSYKDTLMTISLFILMFTILSFSPDLFNDPENFSKANPLVTPQHIKPEWYFLFAYGILRSIPNKLGGTLALLMSVTILMTAPFTHTSHMRPMTFRPLAQMAFWTLIATFITITWTASKPVEPPFIIISQMTSILYFLFFIMNPLLGWTENKIMMNN

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AF220408
EMBL· GenBank· DDBJ
AAF35311.1
EMBL· GenBank· DDBJ
Genomic DNA

Similar Proteins

Disclaimer

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