Reviewed, UniProtKB/Swiss-Prot P12123 (CYB6_ORYSJ)

Names and origin

Protein names

Recommended name:
    Cytochrome b6

Gene names

Name:

petB

Encoded on

Plastid; Chloroplast

Organism

Oryza sativa subsp. japonica (Rice)

Taxonomic identifier

39947 [NCBI]

Taxonomic lineage

Eukaryota › Viridiplantae › Streptophyta › Embryophyta › Tracheophyta › Spermatophyta › Magnoliophyta › Liliopsida › Poales › Poaceae › BEP clade › Ehrhartoideae › Oryzeae › Oryza

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
Coding sequence diversity	Alternative splicing
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...

Alternative products

This entry describes 2 isoforms produced by alternative splicing. [Align] [Select]

Isoform 1 (identifier: P12123-1)

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

Isoform 2 (identifier: P12123-2)

The sequence of this isoform differs from the canonical sequence as follows:
     1-2: MS → MKFSYTVLGGGFGLVTYLN

Note: Unspliced isoform.

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_0000061809
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
Natural variations
	Alternative sequence	1 – 2	2	MS → MKFSYTVLGGGFGLVTYLN in isoform 2. HAMAP MF_00633		VSP_007117

Sequences

	Sequence		Length	Mass (Da)
	Isoform 1 [UniParc]. Last modified October 1, 1989. Version 1. Checksum: C2E389FB10B51E6B	FASTA	215	24,183
	10 20 30 40 50 60 MSKVYDWFEE RLEIQAIADD ITSKYVPPHV NIFYCLGGIT LTCFLVQVAT GFAMTFYYRP 70 80 90 100 110 120 TVTEAFSSVQ YIMTEANFGW LIRSVHRWSA SMMVLMMILH VFRVYLTGGF KKPRELTWVT 130 140 150 160 170 180 GVVLAVLTAS FGVTGYSLPW DQIGYWAVKI VTGVPDAIPV IGSPLVELLR GSASVGQSTL 190 200 210 TRFYSLHTFV LPLLTAVFML MHFLMIRKQG ISGPL
	Isoform 2. Checksum: FAD673459A6038B1	FASTA	232	26,014
	10 20 30 40 50 60 MKFSYTVLGG GFGLVTYLNK VYDWFEERLE IQAIADDITS KYVPPHVNIF YCLGGITLTC 70 80 90 100 110 120 FLVQVATGFA MTFYYRPTVT EAFSSVQYIM TEANFGWLIR SVHRWSASMM VLMMILHVFR 130 140 150 160 170 180 VYLTGGFKKP RELTWVTGVV LAVLTASFGV TGYSLPWDQI GYWAVKIVTG VPDAIPVIGS 190 200 210 220 230 PLVELLRGSA SVGQSTLTRF YSLHTFVLPL LTAVFMLMHF LMIRKQGISG PL

References

	« Hide 'large scale' referencesShow 'large scale' references »
[1]	"Nucleotide sequence of the rice chloroplast apocytochrome b6 gene (petB)." Cote J.C., Wu N.H., Wu R. Plant Mol. Biol. 11:873-874(1988) [Agricola: IND91035204] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA] (ISOFORMS 1 AND 2).
[2]	"The complete sequence of the rice (Oryza sativa) chloroplast genome: intermolecular recombination between distinct tRNA genes accounts for a major plastid DNA inversion during the evolution of the cereals." Hiratsuka J., Shimada H., Whittier R., Ishibashi T., Sakamoto M., Mori M., Kondo C., Honji Y., Sun C.-R., Meng B.-Y., Li Y.-Q., Kanno A., Nishizawa Y., Hirai A., Shinozaki K., Sugiura M. Mol. Gen. Genet. 217:185-194(1989) [PubMed: 2770692] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: cv. Nipponbare.
[3]	"A comparison of rice chloroplast genomes." Tang J., Xia H., Cao M., Zhang X., Zeng W., Hu S., Tong W., Wang J., Wang J., Yu J., Yang H., Zhu L. Plant Physiol. 135:412-420(2004) [PubMed: 15122023] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: cv. Nipponbare.
[4]	"The genome sequence and structure of rice chromosome 1." Sasaki T., Matsumoto T., Yamamoto K., Sakata K., Baba T., Katayose Y., Wu J., Niimura Y., Cheng Z., Nagamura Y., Antonio B.A., Kanamori H., Hosokawa S., Masukawa M., Arikawa K., Chiden Y., Hayashi M., Okamoto M. , Ando T., Aoki H., Arita K., Hamada M., Harada C., Hijishita S., Honda M., Ichikawa Y., Idonuma A., Iijima M., Ikeda M., Ikeno M., Ito S., Ito T., Ito Y., Ito Y., Iwabuchi A., Kamiya K., Karasawa W., Katagiri S., Kikuta A., Kobayashi N., Kono I., Machita K., Maehara T., Mizuno H., Mizubayashi T., Mukai Y., Nagasaki H., Nakashima M., Nakama Y., Nakamichi Y., Nakamura M., Namiki N., Negishi M., Ohta I., Ono N., Saji S., Sakai K., Shibata M., Shimokawa T., Shomura A., Song J., Takazaki Y., Terasawa K., Tsuji K., Waki K., Yamagata H., Yamane H., Yoshiki S., Yoshihara R., Yukawa K., Zhong H., Iwama H., Endo T., Ito H., Hahn J.H., Kim H.-I., Eun M.-Y., Yano M., Jiang J., Gojobori T. Nature 420:312-316(2002) [PubMed: 12447438] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. Strain: cv. Nipponbare.

Cross-references

Sequence databases
EMBLGenBankDDBJ	M35995 Genomic DNA. Translation: AAA85374.1. M35995 Genomic DNA. Translation: AAA85375.1. X15901 Genomic DNA. Translation: CAA33977.1. AY522330 Genomic DNA. No translation available. AP003280 Genomic DNA. No translation available.
PIR	CBRZ6. JQ0256.
RefSeq	NP_039415.1.
3D structure databases
SMR	P12123. Positions 4-215.
ModBase	Search...
Genome annotation databases
GeneID	3131403.
KEGG	osa:3131403.
NMPDR	fig|39947.1.peg.57.
Organism-specific databases
Gramene	P12123.
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_ORYSJ

Accession

Primary (citable) accession number: P12123
Secondary accession number(s): Q36615, Q8S1Q7

Entry history

Integrated into UniProtKB/Swiss-Prot:	October 1, 1989
Last sequence update:	October 1, 1989
Last modified:	June 16, 2009
This is version 76 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)