Q7XYM4 (UCRIA_BIGNA) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Cytochrome b6-f complex iron-sulfur subunit, chloroplastic
EC=1.10.9.1

Alternative name(s):
Plastohydroquinone:plastocyanin oxidoreductase iron-sulfur protein
Rieske iron-sulfur protein
Short name=ISP
Short name=RISP

Gene names

Name:

petC

Organism

Bigelowiella natans (Pedinomonas minutissima) (Chlorarachnion sp. (strain CCMP621))

Taxonomic identifier

227086 [NCBI]

Taxonomic lineage

cellular organisms › Eukaryota › Rhizaria › Cercozoa › Chlorarachniophyceae › Bigelowiella

Protein attributes

Sequence length	252 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at transcript 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.
Catalytic activity	Plastoquinol + 2 oxidized plastocyanin + 2 H+(Side 1) = plastoquinone + 2 reduced plastocyanin + 2 H+(Side 2).
Cofactor	Binds 1 2Fe-2S cluster per subunit 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; Single-pass membrane protein By similarity. Note: The transmembrane helix obliquely spans the membrane in one monomer, and its extrinsic C-terminal domain is part of the other monomer By similarity.
Miscellaneous	This protein is 1 of 2 subunits of the cytochrome b6-f complex that are encoded in the nucleus. The Rieske iron-sulfur protein is a high potential 2Fe-2S protein.
Sequence similarities	Contains 1 Rieske domain.

Ontologies

Keywords
Biological process	Electron transport Transport
Cellular component	Chloroplast Membrane Plastid Thylakoid
Domain	Transit peptide Transmembrane Transmembrane helix
Ligand	2Fe-2S Iron Iron-sulfur Metal-binding
Molecular function	Oxidoreductase
PTM	Disulfide bond
Gene Ontology (GO)
Biological_process	electron transport chain 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	2 iron, 2 sulfur cluster binding Inferred from electronic annotation. Source: UniProtKB-KW metal ion binding Inferred from electronic annotation. Source: UniProtKB-KW plastoquinol--plastocyanin reductase activity Inferred from electronic annotation. Source: EC ubiquinol-cytochrome-c reductase 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
	Transit peptide	1 – ?		Chloroplast Potential
	Chain	? – 252		Cytochrome b6-f complex iron-sulfur subunit, chloroplastic		PRO_0000030686
Regions
	Transmembrane	94 – 114	21	Helical; Potential
	Domain	141 – 235	95	Rieske
Sites
	Metal binding	181	1	Iron-sulfur (2Fe-2S) By similarity
	Metal binding	183	1	Iron-sulfur (2Fe-2S); via pros nitrogen By similarity
	Metal binding	199	1	Iron-sulfur (2Fe-2S) By similarity
	Metal binding	202	1	Iron-sulfur (2Fe-2S); via pros nitrogen By similarity
Amino acid modifications
	Disulfide bond	186 ↔ 201		By similarity

Sequences

	Sequence		Length	Mass (Da)
	Q7XYM4 [UniParc]. Last modified October 1, 2003. Version 1. Checksum: 9BDD2C12697EF92A	FASTA	252	26,862
	10 20 30 40 50 60 MAQSRSLLLS IAVNALLVGV LLYSVAVNRT QEGSLQLSAV RGKIAAPRTS FQNAVSRVSR 70 80 90 100 110 120 NQLPSSSRKA VAQAFLSNPD MVPDMGKRKL MNNLVLAAVA PVVASAGGCY LYYFYPPQTG 130 140 150 160 170 180 GGGGAVGALD ALGNPVSAES WFKSHKKNAR DLVQGIKGDP TYLIVNDDGS TLNSYGLNAI 190 200 210 220 230 240 CTHLGCVVPW DAASNKFKCP CHGSQYAPDG HVVRGPAPRP LQLAHVEDDN GKILLSPWTE 250 TDFRTGEKPW WA

References

[1]

"Lateral gene transfer and the evolution of plastid-targeted proteins in the secondary plastid-containing alga Bigelowiella natans." Archibald J.M., Rogers M.B., Toop M., Ishida K., Keeling P.J. Proc. Natl. Acad. Sci. U.S.A. 100:7678-7683(2003) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA].

Cross-references

Sequence databases
EMBL GenBank DDBJ	AY267656 mRNA. Translation: AAP79170.1.
3D structure databases
ProteinModelPortal	Q7XYM4.
SMR	Q7XYM4. Positions 84-252.
ModBase	Search...
Protocols and materials databases
StructuralBiologyKnowledgebase	Search...
Family and domain databases
Gene3D	2.102.10.10. 1 hit.
InterPro	IPR014909. Cyt_b6-f_cplx_Fe-S_su. IPR017941. Rieske_2Fe-2S. IPR014349. Rieske_Fe-S_prot. IPR005805. Rieske_Fe-S_prot_C. [Graphical view]
PANTHER	PTHR10134. PTHR10134. 1 hit.
Pfam	PF08802. CytB6-F_Fe-S. 1 hit. PF00355. Rieske. 1 hit. [Graphical view]
PRINTS	PR00162. RIESKE.
SUPFAM	SSF50022. Rieske_dom. 1 hit.
PROSITE	PS51296. RIESKE. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

UCRIA_BIGNA

Accession

Primary (citable) accession number: Q7XYM4

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 5, 2005
Last sequence update:	October 1, 2003
Last modified:	April 3, 2013
This is version 56 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)