P24954 (CYB_DICBI) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Cytochrome b

Alternative name(s):
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

Diceros bicornis (Black rhinoceros)

Taxonomic identifier

9805 [NCBI]

Taxonomic lineage

cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Deuterostomia › Chordata › Craniata › Vertebrata › Gnathostomata › Teleostomi › Euteleostomi › Sarcopterygii › Tetrapoda › Amniota › Mammalia › Theria › Eutheria › Laurasiatheria › Perissodactyla › Rhinocerotidae › Diceros

Protein attributes

Sequence length	379 AA.
Sequence status	Complete.
Protein existence	Inferred from homology

General annotation (Comments)

Function	Component of the ubiquinol-cytochrome c reductase complex (complex III or cytochrome b-c1 complex), which is a respiratory chain that generates an electrochemical potential coupled to ATP synthesis By similarity.
Cofactor	Binds 2 heme groups non-covalently By similarity.
Subunit structure	The bc1 complex contains 11 subunits: 3 respiratory subunits (cytochrome b, cytochrome c1 and Rieske/UQCRFS1), 2 core proteins (UQCRC1/QCR1 and UQCRC2/QCR2) and 6 low-molecular weight proteins (UQCRH/QCR6, UQCRB/QCR7, UQCRQ/QCR8, UQCR10/QCR9, UQCR11/QCR10 and a cleavage product of Rieske/UQCRFS1) By similarity.
Subcellular location	Mitochondrion inner membrane; Multi-pass membrane protein By similarity.
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 By similarity.
Sequence similarities	Belongs to the cytochrome b family.

Ontologies

Keywords
Biological process	Electron transport Respiratory chain Transport
Cellular component	Membrane Mitochondrion Mitochondrion inner membrane
Domain	Transmembrane Transmembrane helix
Ligand	Heme Iron Metal-binding
Gene Ontology (GO)
Biological_process	respiratory electron transport chain Inferred from electronic annotation. Source: InterPro
Cellular_component	integral to membrane Inferred from electronic annotation. Source: UniProtKB-KW mitochondrial inner membrane Inferred from electronic annotation. Source: UniProtKB-SubCell respiratory chain Inferred from electronic annotation. Source: UniProtKB-KW
Molecular_function	electron carrier activity Inferred from electronic annotation. Source: InterPro metal ion binding Inferred from electronic annotation. Source: UniProtKB-KW oxidoreductase activity Inferred from electronic annotation. Source: InterPro
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Chain	1 – 379	379	Cytochrome b		PRO_0000060882
Regions
	Transmembrane	33 – 53	21	Helical; Potential
	Transmembrane	76 – 96	21	Helical; Potential
	Transmembrane	115 – 135	21	Helical; Potential
	Transmembrane	150 – 170	21	Helical; Potential
	Transmembrane	178 – 198	21	Helical; Potential
	Transmembrane	229 – 249	21	Helical; Potential
	Transmembrane	288 – 308	21	Helical; Potential
	Transmembrane	323 – 343	21	Helical; Potential
	Transmembrane	346 – 366	21	Helical; Potential
Sites
	Metal binding	83	1	Iron 1 (heme b562 axial ligand)
	Metal binding	97	1	Iron 2 (heme b566 axial ligand)
	Metal binding	182	1	Iron 1 (heme b562 axial ligand)
	Metal binding	196	1	Iron 2 (heme b566 axial ligand)

Sequences

	Sequence		Length	Mass (Da)
	P24954 [UniParc]. Last modified March 1, 1992. Version 1. Checksum: 225851C2193E6644	FASTA	379	42,664
	10 20 30 40 50 60 MTNIRKSHPL IKIINHSFID LPTPSNISAW WNFGSLLGIC LILQILTGLF LAMHYTPDTT 70 80 90 100 110 120 TAFSSVAHIC REVNYGWIIR YLHANGASMF FICLFIHMGR GLYYGSYTFL KTWNIGVILL 130 140 150 160 170 180 LTVMATAFMG YVLPWGQMSF WGATVITNLL SAIPYIGTTL VEWIWGGFSV DKATLTRFFA 190 200 210 220 230 240 FHFILPFIIS ALAITHLLFL HETGSNNPSG IPSNMDKIPF HPYYTIKDIL GILLLILTLL 250 260 270 280 290 300 TLVLFSPHHL GDPDNYTPAT PLNTPPHIKP EWYFLFAYAI LRSVPNKLGG VLALALSILI 310 320 330 340 350 360 LALIPILHTS KQRSMMFRPL SQCMFWLLVA DLLTLTWIGG QPVEHPFIII GQLASILYFS 370 LILVLMPLAG IIENNLLKW

References

[1]	"Evolution of the cytochrome b gene of mammals." Irwin D.M., Kocher T.D., Wilson A.C. J. Mol. Evol. 32:128-144(1991) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].

Cross-references

Sequence databases
EMBL GenBank DDBJ	X56283 Genomic DNA. Translation: CAA39730.1.
PIR	S17408.
3D structure databases
ProteinModelPortal	P24954.
SMR	P24954. Positions 1-379.
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Phylogenomic databases
HOVERGEN	HBG017694.
Family and domain databases
InterPro	IPR016175. Cyt_b/b6. IPR005798. Cyt_b/b6_C. IPR005797. Cyt_b/b6_N. IPR016174. Di-haem_cyt_TM. [Graphical view]
PANTHER	PTHR19271. PTHR19271. 1 hit.
Pfam	PF00032. Cytochrom_B_C. 1 hit. PF13631. Cytochrom_B_N_2. 1 hit. [Graphical view]
SUPFAM	SSF81648. Cytochrome_b/b6_C. 1 hit. SSF81342. Transmembr_di-haem_cytochrome. 1 hit.
PROSITE	PS51003. CYTB_CTER. 1 hit. PS51002. CYTB_NTER. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

CYB_DICBI

Accession

Primary (citable) accession number: P24954

Entry history

Integrated into UniProtKB/Swiss-Prot:	March 1, 1992
Last sequence update:	March 1, 1992
Last modified:	May 1, 2013
This is version 67 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Chordata Protein Annotation Program