Annotation rule MF_00633
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General rule information [?]

Accession MF_00633
Dates 4-APR-2003 (Created)
2-DEC-2010 (Last updated, Version 46)
Name Cytb6_f_cytb6
Scope Bacteria; Cyanobacteria
Bacteria; Heliobacteriaceae
Plastid
Templates Q00471 (CYB6_CHLRE); P00165 (CYB6_SPIOL): [Recover all]

Propagated annotation [?]


Identifier, protein and gene names [?]

Identifier
CYB6
Protein name
RecName: Full=Cytochrome b6;
case not <OC:Heliobacteriaceae>
Gene name
petB
else case <OC:Heliobacteriaceae>
Gene name
petB, cytB
end case

Comments [?]

case <OC:Heliobacteriaceae>
Function Component of the cytochrome bc complex which donates electrons to the photosynthetic reaction center (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 The subunits of the cytochrome bc complex are a Rieske Fe-S protein (PetC), cytochrome b6 (PetB), subunit IV (PetD), and a diheme cytochrome c (PetX) (By similarity).
else case not <OC:Heliobacteriaceae>
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 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).
end case
case <OC:Heliobacteriaceae>
Subcellular location Cell membrane; Multi-pass membrane protein (By similarity).
else case <OG:Chloroplast>
Subcellular location Plastid, chloroplast thylakoid membrane; Multi-pass membrane protein (By similarity).
else case <OC:Gloeobacter>
Subcellular location Cell inner membrane; Multi-pass membrane protein (By similarity).
else
Subcellular location Cellular thylakoid membrane; Multi-pass membrane protein (By similarity).
end case
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).
Similarity Belongs to the cytochrome b family. PetB subfamily.

Keywords [?]

case <OC:Gloeobacter>
else case <OG:Chloroplast> or <Property:Thylakoid>
else case <OC:Heliobacteriaceae>
end case

Gene Ontology [?]

case <OC:Heliobacteriaceae> or <OC:Gloeobacter>
GO:0005886; Cellular component: plasma membrane.
else case <OG:Chloroplast>
GO:0009535; Cellular component: chloroplast thylakoid membrane.
else
GO:0042651; Cellular component: thylakoid membrane.
end case
GO:0045158; Molecular function: electron transporter, transferring electrons within cytochrome b6/f complex of photosystem II activity.
GO:0015979; Biological process: photosynthesis.
GO:0055114; Biological process: oxidation-reduction process.

Cross-references [?]

Pfam PF00033; Cytochrom_B_N; 1;
PROSITE PS51002; CYTB_NTER; 1;

Features [?]

From: CYB6_ARATH (P56773)
Key     From     To       Description   Tag   Condition   FTGroup
TRANSMEM     32     52       Helical; (Potential)        
TRANSMEM     90     110       Helical; (Potential)        
TRANSMEM     116     136       Helical; (Potential)        
TRANSMEM     186     206       Helical; (Potential)        
METAL     86     86       Iron (heme 2 axial ligand) (By similarity)     H  
METAL     100     100       Iron (heme 1 axial ligand) (By similarity)     H  
METAL     187     187       Iron (heme 2 axial ligand) (By similarity)     H  
METAL     202     202       Iron (heme 1 axial ligand) (By similarity)     H  
BINDING     35     35       Heme 1 (covalent; via 1 link) (By similarity)     C  

Additional information [?]

Size range 213-222 amino acids
Related rules None
Fusion None
Comments In maize and tobacco position 204 has been shown to undergo RNA editing to change the codon from Pro to Leu. It has therefore been suggested to occur in all other plants where this codon is Pro (CCA -> CTA). In C.reinhardtii an engineered Pro mutation at this position is unable to assemble intact complex, giving strength to this suggestion.