Reviewed, UniProtKB/Swiss-Prot Q20ET5 (CYB6_OLTVI)

Names and origin

Protein names

Recommended name:
    Cytochrome b6

Gene names

Name:

petB

Encoded on

Plastid; Chloroplast

Organism

Oltmannsiellopsis viridis (Marine flagellate)

Taxonomic identifier

51324 [NCBI]

Taxonomic lineage

Eukaryota › Viridiplantae › Chlorophyta › Oltmannsiellopsis

Protein attributes

Sequence length	215 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Inferred from homology.

General annotation (Comments)

Function	Component of the cytochrome b6-f complex, which mediates electron transfer between photosystem II (PSII) and photosystem I (PSI), cyclic electron flow around PSI, and state transitions By similarity.
Cofactor	Binds 2 heme groups. One heme group is bound covalently by a single cysteine link, the other one non-covalently By similarity.
Subunit structure	The 4 large subunits of the cytochrome b6-f complex are cytochrome b6, subunit IV (17 kDa polypeptide, petD), cytochrome f and the Rieske protein, while the 4 small subunits are petG, petL, petM and petN. The complex functions as a dimer By similarity.
Subcellular location	Plastid › chloroplast thylakoid membrane; Multi-pass membrane protein By similarity.
Miscellaneous	Heme 1 (or BH or b566) is high-potential and absorbs at about 566 nm, and heme 2 (or BL or b562) is low-potential and absorbs at about 562 nm By similarity.
Sequence similarities	Belongs to the cytochrome b family. PetB subfamily.

Ontologies

Keywords
Biological process	Electron transport Photosynthesis Transport
Cellular component	Chloroplast Membrane Plastid Thylakoid
Domain	Transmembrane
Ligand	Heme Iron Metal-binding
Gene Ontology (GO)
Biological process	photosynthesis Inferred from electronic annotation. Source: HAMAP respiratory electron transport chain Inferred from electronic annotation. Source: InterPro transport Inferred from electronic annotation. Source: UniProtKB-KW
Cellular component	chloroplast thylakoid membrane Inferred from electronic annotation. Source: UniProtKB-SubCell integral to membrane Inferred from electronic annotation. Source: UniProtKB-KW
Molecular function	electron transporter, transferring electrons within cytochrome b6/f complex of photosystem II activity Inferred from electronic annotation. Source: HAMAP iron 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 – 215	215	Cytochrome b6 HAMAP MF_00633		PRO_0000275326
Regions
	Transmembrane	32 – 52	21	Potential
	Transmembrane	90 – 110	21	Potential
	Transmembrane	116 – 136	21	Potential
	Transmembrane	186 – 206	21	Potential
Sites
	Metal binding	86	1	Iron (heme 2 axial ligand) By similarity
	Metal binding	100	1	Iron (heme 1 axial ligand) By similarity
	Metal binding	187	1	Iron (heme 2 axial ligand) By similarity
	Metal binding	202	1	Iron (heme 1 axial ligand) By similarity
	Binding site	35	1	Heme 1 (covalent; via 1 link) By similarity

Sequences

	Sequence		Length	Mass (Da)
	Q20ET5-1 [UniParc]. Last modified April 18, 2006. Version 1. Checksum: ED8D6B97E45BABFF	FASTA	215	24,030
	10 20 30 40 50 60 MSKVYEWFDE RLELQAIADD VSSKYVPPHV NIFYCLGGIT FTSFLVQVAT GFAMTFYYRP 70 80 90 100 110 120 TVAEAFASVQ YIMTDVNFGW LIRSIHRWSA SMMVMMMILH VFRVYLTGGF KRPRELTWVT 130 140 150 160 170 180 GVIMAVCTVS FGVTGYSLPW DQVGYWAVKI VTGVPDAIPV VGAALVELLR GGVGVGQATL 190 200 210 TRFYSLHTFV LPLATAVFML AHFLMIRKQG ISGPL

References

[1]

"The complete chloroplast DNA sequence of the green alga Oltmannsiellopsis viridis reveals a distinctive quadripartite architecture in the chloroplast genome of early diverging ulvophytes." Pombert J.-F., Lemieux C., Turmel M. BMC Biol. 4:3-3(2006) [PubMed: 16472375] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].

Cross-references

Sequence databases
EMBLGenBankDDBJ	DQ291132 Genomic DNA. Translation: ABB81978.1. DQ291132 Genomic DNA. Translation: ABB82012.1.
RefSeq	YP_635851.1. YP_635910.1.
3D structure databases
SMR	Q20ET5. Positions 4-215.
ModBase	Search...
Genome annotation databases
GeneID	4100074. 4100115.
Family and domain databases
HAMAP	MF_00633. [Tree]
InterPro	IPR016175. Cyt_b/b6. IPR005797. Cyt_b/b6_N. [Graphical view]
Gene3D	G3DSA:1.20.810.10. Cytochrome_b/b6. 1 hit.
PANTHER	PTHR19271. Cytochrome_b/b6. 1 hit.
Pfam	PF00033. Cytochrom_B_N. 1 hit. [Graphical view]
PROSITE	PS51002. CYTB_NTER. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

CYB6_OLTVI

Accession

Primary (citable) accession number: Q20ET5

Entry history

Integrated into UniProtKB/Swiss-Prot:	February 6, 2007
Last sequence update:	April 18, 2006
Last modified:	June 16, 2009
This is version 22 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

HAMAP (High-quality Automated and Manual Annotation of microbial Proteomes)