P56321 (CYB6_CHLVU) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Cytochrome b6

Gene names

Name:

petB

Encoded on

Plastid; Chloroplast

Organism

Chlorella vulgaris (Green alga)

Taxonomic identifier

3077 [NCBI]

Taxonomic lineage

Eukaryota › Viridiplantae › Chlorophyta › Trebouxiophyceae › Chlorellales › Chlorellaceae › Chlorella

Protein attributes

Sequence length	215 AA.
Sequence status	Complete.
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. HAMAP MF_00633
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 HAMAP MF_00633.
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. HAMAP MF_00633
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 Transmembrane helix
Ligand	Heme Iron Metal-binding
Gene Ontology (GO)
Biological process	photosynthesis Inferred from electronic annotation. Source: UniProtKB-KW 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: InterPro heme binding Inferred from electronic annotation. Source: InterPro 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_0000061788
Regions
	Transmembrane	32 – 52	21	Helical; Potential
	Transmembrane	90 – 110	21	Helical; Potential
	Transmembrane	116 – 136	21	Helical; Potential
	Transmembrane	186 – 206	21	Helical; 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)
	P56321 [UniParc]. Last modified July 15, 1998. Version 1. Checksum: 3A04183319E3A64E	FASTA	215	24,087
	10 20 30 40 50 60 MGKVYDWFEE RLEIQSIADD ISSKYVPPHV NIFYCIGGIT FTCFLVQVAT GFAMTFYYRP 70 80 90 100 110 120 TVAEAFASVQ YIMTEVNFGW LIRSIHRWSA SMMVLMMILH VCRVYLTGGF KKPRELTWVT 130 140 150 160 170 180 GVIMAVCTVS FGVTGYSLPW DQIGYWAVKI VTGVPDAIPV VGPALVELLR GGVGVGQSTL 190 200 210 TRFYSLHTFV LPLATAVFML MHFLMIRKQG ISGPL

References

[1]

"Complete nucleotide sequence of the chloroplast genome from the green alga Chlorella vulgaris: the existence of genes possibly involved in chloroplast division." Wakasugi T., Nagai T., Kapoor M., Sugita M., Ito M., Ito S., Tsudzuki J., Nakashima K., Tsudzuki T., Suzuki Y., Hamada A., Ohta T., Inamura A., Yoshinaga K., Sugiura M. Proc. Natl. Acad. Sci. U.S.A. 94:5967-5972(1997) [PubMed: 9159184] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: IAM C-27 / Tamiya.

Cross-references

Sequence databases
EMBL GenBank DDBJ	AB001684 Genomic DNA. Translation: BAA57914.1.
PIR	T07266.
RefSeq	NP_045838.1. NC_001865.1.
3D structure databases
ProteinModelPortal	P56321.
SMR	P56321. Positions 4-215.
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Genome annotation databases
GeneID	809116.
Phylogenomic databases
ProtClustDB	CHL00070.
Family and domain databases
HAMAP	MF_00633. Cytb6_f_cytb6. [Tree]
InterPro	IPR016175. Cyt_b/b6. IPR005797. Cyt_b/b6_N. IPR023530. Cyt_B6_PetB. IPR016174. Di-haem_cyt_TM. [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]
PIRSF	PIRSF000032. Cytochrome_b6. 1 hit.
SUPFAM	SSF81342. Transmembr_di-haem_cytochrome. 1 hit.
PROSITE	PS51002. CYTB_NTER. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

CYB6_CHLVU

Accession

Primary (citable) accession number: P56321

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 15, 1998
Last sequence update:	July 15, 1998
Last modified:	July 27, 2011
This is version 66 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Plant Protein Annotation Program