Reviewed, UniProtKB/Swiss-Prot P0A384 (CYB6_ANASP)

Names and origin

Protein names

Recommended name:
    Cytochrome b6

Gene names

Name:	petB
Ordered Locus Names:	alr3421

Organism

Anabaena sp. (strain PCC 7120) [Complete proteome] [HAMAP]

Taxonomic identifier

103690 [NCBI]

Taxonomic lineage

Bacteria › Cyanobacteria › Nostocales › Nostocaceae › Nostoc

Protein attributes

Sequence length	215 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Evidence at protein level.

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	Cellular 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	Membrane Thylakoid
Domain	Transmembrane
Ligand	Heme Iron Metal-binding
Technical term	3D-structure Complete proteome
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	integral to membrane Inferred from electronic annotation. Source: UniProtKB-KW thylakoid membrane Inferred from electronic annotation. Source: UniProtKB-SubCell
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_0000061824
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)
	P0A384-1 [UniParc]. Last modified March 15, 2005. Version 1. Checksum: 272ECF1C60C4A963	FASTA	215	24,273
	10 20 30 40 50 60 MANVYDWFEE RLEIQAIAED VTSKYVPPHV NIFYCLGGIT LVCFLIQFAT GFAMTFYYKP 70 80 90 100 110 120 TVAEAYSSVQ YIMNEVNFGW LIRSIHRWSA SMMVLMMILH VFRVYLTGGF KKPRELTWVS 130 140 150 160 170 180 GVILAVITVS FGVTGYSLPW DQVGYWAVKI VSGVPEAIPV VGVLISDLLR GGSSVGQATL 190 200 210 TRYYSAHTFV LPWLIAVFML FHFLMIRKQG ISGPL

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"b6f complex of Anabaena sp." Arnold M. Submitted (MAY-2001) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[2]	"Complete genomic sequence of the filamentous nitrogen-fixing cyanobacterium Anabaena sp. strain PCC 7120." Kaneko T., Nakamura Y., Wolk C.P., Kuritz T., Sasamoto S., Watanabe A., Iriguchi M., Ishikawa A., Kawashima K., Kimura T., Kishida Y., Kohara M., Matsumoto M., Matsuno A., Muraki A., Nakazaki N., Shimpo S., Sugimoto M. , Takazawa M., Yamada M., Yasuda M., Tabata S. DNA Res. 8:205-213(2001) [PubMed: 11759840] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].

Cross-references

Sequence databases

EMBLGenBankDDBJ

AJ319645 Genomic DNA. Translation: CAC39602.1.
BA000019 Genomic DNA. Translation: BAB75120.1.

PIR

AF2233.

RefSeq

NP_487461.1.

3D structure databases

PDBPDBe

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
2ZT9	X-ray	3.00	A	1-215	[»]

SMR

P0A384. Positions 13-214.

ModBase

Search...

Genome annotation databases

GeneID

1107019.

GenomeReviews

Gene locus alr3421 in contig BA000019_GR.

KEGG

ana:alr3421.

Organism-specific databases

CMR

Search...

Phylogenomic databases

HOGENOM

P0A384.

OMA

P0A384. QATLTRF.

Enzyme and pathway databases

BioCyc

NSP103690:ALR3421-MON.

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_ANASP

Accession

Primary (citable) accession number: P0A384
Secondary accession number(s): Q9L3Q1

Entry history

Integrated into UniProtKB/Swiss-Prot:	March 15, 2005
Last sequence update:	March 15, 2005
Last modified:	June 16, 2009
This is version 35 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)