P00164 (CYB_TRYBB) 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

Trypanosoma brucei brucei

Taxonomic identifier

5702 [NCBI]

Taxonomic lineage

cellular organisms › Eukaryota › Euglenozoa › Kinetoplastida › Trypanosomatidae › Trypanosoma › Trypanozoon › Trypanosoma brucei

Protein attributes

Sequence length	363 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 main subunits of complex b-c1 are: cytochrome b, cytochrome c1 and the Rieske protein 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 – 363	363	Cytochrome b		PRO_0000061690
Regions
	Transmembrane	31 – 51	21	Helical; Potential
	Transmembrane	57 – 77	21	Helical; Potential
	Transmembrane	79 – 99	21	Helical; Potential
	Transmembrane	103 – 123	21	Helical; Potential
	Transmembrane	138 – 158	21	Helical; Potential
	Transmembrane	173 – 193	21	Helical; Potential
	Transmembrane	225 – 245	21	Helical; Potential
	Transmembrane	287 – 307	21	Helical; Potential
	Transmembrane	321 – 341	21	Helical; Potential
	Transmembrane	342 – 362	21	Helical; Potential
Sites
	Metal binding	74	1	Iron 1 (heme b562 axial ligand)
	Metal binding	88	1	Iron 2 (heme b566 axial ligand)
	Metal binding	175	1	Iron 1 (heme b562 axial ligand)
	Metal binding	189	1	Iron 2 (heme b566 axial ligand)

Sequences

	Sequence		Length	Mass (Da)
	P00164 [UniParc]. Last modified July 21, 1986. Version 1. Checksum: 2A37CD827E55923B	FASTA	363	43,455
	10 20 30 40 50 60 MLYKSGEKRK GLLMSGCLYR IYGVGFSLGF FIALQIICGV CLAWLFFSCF ICSNWYFVLF 70 80 90 100 110 120 LWDFDLGFVI RSVHICFTSL LYLLLYIHIF KSITLIILFD THILVWFIGF ILFVFIIIIA 130 140 150 160 170 180 FIGYVLPCTM MSYWGLTVFS NIIATVPILG IWLCYWIWGS EFINDFTLLK LHVLHVLLPF 190 200 210 220 230 240 ILLIILILHL FCLHYFMSSD AFCDRFAFYC ERLSFCMWFY LRDMFLAFSI LLCMMYVIFI 250 260 270 280 290 300 NWYFVFHEES WVIVDTLKTS DKILPEWFFL YLFGFLKAIP DKFMGLFLMV ILLFSLFLFI 310 320 330 340 350 360 LNCILWFVYC RSSLLWLTYS LILFYSIWMS GFLALYVVLA YPIWMELQYW VLLLFLLIVC RLD

References

[1]

"The nucleotide sequence of a segment of Trypanosoma brucei mitochondrial maxi-circle DNA that contains the gene for apocytochrome b and some unusual unassigned reading frames." Benne R., de Vries B.F., van den Burg J., Klaver B. Nucleic Acids Res. 11:6925-6941(1983) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] (KINETOPLAST).

Cross-references

Sequence databases
EMBL GenBank DDBJ	X00017 Genomic DNA. Translation: CAA24915.1.
PIR	CBUTB. A00160.
3D structure databases
ProteinModelPortal	P00164.
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Family and domain databases
Gene3D	1.20.810.10. 1 hit.
InterPro	IPR016175. Cyt_b/b6. IPR005798. Cyt_b/b6_C. IPR005797. Cyt_b/b6_N. IPR027387. Cytb/b6-like. 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_TRYBB

Accession

Primary (citable) accession number: P00164

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 21, 1986
Last sequence update:	July 21, 1986
Last modified:	May 29, 2013
This is version 77 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)