Protein: Cytochrome b (EC 7.1.1.8) (Complex III subunit 3) (Complex III subunit CYTB) (Complex III subunit III) (Cytochrome b-c1 complex subunit 3) (Cytochrome b-c1 complex subunit CYTB) (Ubiquinol-cytochrome c oxidoreductase complex cytochrome b subunit) (P00163)
Organism: Saccharomyces cerevisiae (strain ATCC 204508 / S288c) (Baker's yeast)
Function: Component of the ubiquinol-cytochrome c oxidoreductase, a multisubunit transmembrane complex that is part of the mitochondrial electron transport chain which drives oxidative phosphorylation. The respiratory chain contains 3 multisubunit complexes succinate dehydrogenase (complex II, CII), ubiquinol-cytochrome c oxidoreductase (cytochrome b-c1 complex, complex III, CIII) and cytochrome c oxidase (complex IV, CIV), that cooperate to transfer electrons derived from NADH and succinate to molecular oxygen, creating an electrochemical gradient over the inner membrane that drives transmembrane transport and the ATP synthase. The cytochrome b-c1 complex catalyzes electron transfer from ubiquinol to cytochrome c, linking this redox reaction to translocation of protons across the mitochondrial inner membrane, with protons being carried across the membrane as hydrogens on the quinol. In the process called Q cycle, 2 protons are consumed from the matrix, 4 protons are released into the intermembrane space and 2 electrons are passed to cytochrome c (Probable). Cytochrome b is a catalytic core subunit containing 2 b-type hemes BL and BH topographically segregated in the quinone reduction (Qi) and quinol oxidation (Q0) sites on opposite sides of the membrane.
Subcellular location: Mitochondrion inner membrane {ECO:0000269|PubMed:18390544, ECO:0000269|PubMed:30598554, ECO:0000269|PubMed:8031140}; Multi-pass membrane protein {ECO:0000269|PubMed:10873857, ECO:0000269|PubMed:11880631, ECO:0000269|PubMed:18390544, ECO:0000269|PubMed:30598554, ECO:0000269|PubMed:8031140}.
Sequence: MAFRKSNVYLSLVNSYIIDSPQPSSINYWWNMGSLLGLCLVIQIVTGIFMAMHYSSNIELAFSSVEHIMRDVHNGYILRYLHANGASFFFMVMFMHMAKGLYYGSYRSPRVTLWNVGVIIFILTIATAFLGYCCVYGQMSHWGATVITNLFSAIPFVGNDIVSWLWGGFSVSNPTIQRFFALHYLVPFIIAAMVIMHLMALHIHGSSNPLGITGNLDRIPMHSYFIFKDLVTVFLFMLILALFVFYSPNTLGHPDNYIPGNPLVTPASIVPEWYLLPFYAILRSIPDKLLGVITMFAAILVLLVLPFTDRSVVRGNTFKVLSKFFFFIFVFNFVLLGQIGACHVEVPYVLMGQIATFIYFAYFLIIVPVISTIENVLFYIGRVNK
InterPro domains: - IPR005798: Cytochrome b/b6, C-terminal (domain) [211-381]
- IPR048259: Cytochrome b/b6, N-terminal domain, eukaryotic/bacterial (domain) [8-207]
- IPR048260: Cytochrome b/b6, C-terminal domain, eukaryotic/bacterial (domain) [208-355]
- IPR016174: Di-haem cytochrome, transmembrane (homologous_superfamily) [3-261]
- IPR005797: Cytochrome b/b6, N-terminal domain (domain) [1-210]
- IPR030689: Cytochrome b (family) [2-385]
- IPR036150: Cytochrome b/b6, C-terminal domain superfamily (homologous_superfamily) [262-382]
- IPR027387: Cytochrome b/b6-like domain superfamily (homologous_superfamily) [1-385]
Interaction partners: - Cytochrome b-c1 complex subunit Rieske, mitochondrial
- Cytochrome c oxidase subunit 13, mitochondrial
- Cytochrome c oxidase subunit 3
- Cytochrome b-c1 complex subunit 1, mitochondrial
- Cytochrome c oxidase subunit 7, mitochondrial
- Cytochrome c oxidase subunit 2
- Cytochrome c1, heme protein, mitochondrial
- Cytochrome b-c1 complex subunit 8, mitochondrial
- Cytochrome b-c1 complex subunit 2, mitochondrial
- Cytochrome c oxidase subunit 12, mitochondrial
Gene Ontology annotations:
Molecular Function (MF): GO:0003674 (molecular function), GO:0005488 (binding), GO:0005215 (transporter activity), GO:0022857 (transmembrane transporter activity), GO:0097159 (organic cyclic compound binding), GO:1901363 (heterocyclic compound binding), GO:0005515 (protein binding), GO:0140318 (protein transporter activity), GO:0003676 (nucleic acid binding), GO:0008320 (protein transmembrane transporter activity), GO:0022884 (macromolecule transmembrane transporter activity), GO:0003723 (RNA binding), GO:0003729 (mRNA binding)
Biological Process (BP): GO:0008150 (biological process), GO:0008152 (metabolic process), GO:0009987 (cellular process), GO:0044237 (cellular metabolic process), GO:0006091 (generation of precursor metabolites and energy), GO:0015980 (energy derivation by oxidation of organic compounds), GO:0022900 (electron transport chain), GO:0045333 (cellular respiration), GO:0022904 (respiratory electron transport chain), GO:0019646 (aerobic electron transport chain), GO:0009060 (aerobic respiration), GO:0042773 (ATP synthesis coupled electron transport), GO:0006119 (oxidative phosphorylation), GO:0042775 (mitochondrial ATP synthesis coupled electron transport), GO:0006122 (mitochondrial electron transport, ubiquinol to cytochrome c)
Cellular Component (CC): GO:0005575 (cellular component), GO:0032991 (protein-containing complex), GO:0110165 (cellular anatomical entity), GO:0005622 (intracellular anatomical structure), GO:0043226 (organelle), GO:0098798 (mitochondrial protein-containing complex), GO:0016020 (membrane), GO:0070469 (respirasome), GO:0098796 (membrane protein complex), GO:1990351 (transporter complex), GO:0031975 (envelope), GO:1902494 (catalytic complex), GO:0005737 (cytoplasm), GO:0031090 (organelle membrane), GO:0031967 (organelle envelope), GO:0005746 (mitochondrial respirasome), GO:0098803 (respiratory chain complex), GO:0043229 (intracellular organelle), GO:0070069 (cytochrome complex), GO:0098800 (inner mitochondrial membrane protein complex), GO:0005739 (mitochondrion), GO:1902495 (transmembrane transporter complex), GO:1990204 (oxidoreductase complex), GO:0043227 (membrane-bounded organelle), GO:0005740 (mitochondrial envelope), GO:0043231 (intracellular membrane-bounded organelle), GO:0045275 (respiratory chain complex III), GO:0019866 (organelle inner membrane), GO:0031966 (mitochondrial membrane), GO:0005750 (mitochondrial respiratory chain complex III), GO:0005743 (mitochondrial inner membrane)