ID   CYB6_CHAGL              Reviewed;         215 AA.
AC   Q8M9Z4;
DT   11-APR-2003, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-2002, sequence version 1.
DT   22-NOV-2017, entry version 80.
DE   RecName: Full=Cytochrome b6 {ECO:0000255|HAMAP-Rule:MF_00633};
GN   Name=petB {ECO:0000255|HAMAP-Rule:MF_00633};
OS   Chaetosphaeridium globosum (Charophycean green alga) (Herposteiron
OS   globosum).
OG   Plastid; Chloroplast.
OC   Eukaryota; Viridiplantae; Streptophyta; Coleochaetophyceae;
OC   Coleochaetales; Chaetosphaeridiaceae; Chaetosphaeridium.
OX   NCBI_TaxID=96477;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=M1311;
RX   PubMed=12161560; DOI=10.1073/pnas.162203299;
RA   Turmel M., Otis C., Lemieux C.;
RT   "The chloroplast and mitochondrial genome sequences of the charophyte
RT   Chaetosphaeridium globosum: insights into the timing of the events
RT   that restructured organelle DNAs within the green algal lineage that
RT   led to land plants.";
RL   Proc. Natl. Acad. Sci. U.S.A. 99:11275-11280(2002).
CC   -!- FUNCTION: Component of the cytochrome b6-f complex, which mediates
CC       electron transfer between photosystem II (PSII) and photosystem I
CC       (PSI), cyclic electron flow around PSI, and state transitions.
CC       {ECO:0000255|HAMAP-Rule:MF_00633}.
CC   -!- COFACTOR:
CC       Name=heme; Xref=ChEBI:CHEBI:30413;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_00633};
CC       Note=Binds 2 heme groups. One heme group is bound covalently by a
CC       single cysteine link, the other one non-covalently.
CC       {ECO:0000255|HAMAP-Rule:MF_00633};
CC   -!- SUBUNIT: The 4 large subunits of the cytochrome b6-f complex are
CC       cytochrome b6, subunit IV (17 kDa polypeptide, PetD), cytochrome f
CC       and the Rieske protein, while the 4 small subunits are PetG, PetL,
CC       PetM and PetN. The complex functions as a dimer.
CC       {ECO:0000255|HAMAP-Rule:MF_00633}.
CC   -!- SUBCELLULAR LOCATION: Plastid, chloroplast thylakoid membrane
CC       {ECO:0000255|HAMAP-Rule:MF_00633}; Multi-pass membrane protein
CC       {ECO:0000255|HAMAP-Rule:MF_00633}.
CC   -!- MISCELLANEOUS: Heme 1 (or BH or b566) is high-potential and
CC       absorbs at about 566 nm, and heme 2 (or BL or b562) is low-
CC       potential and absorbs at about 562 nm. {ECO:0000255|HAMAP-
CC       Rule:MF_00633}.
CC   -!- SIMILARITY: Belongs to the cytochrome b family. PetB subfamily.
CC       {ECO:0000255|HAMAP-Rule:MF_00633}.
CC   ---------------------------------------------------------------------------
CC   Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC   Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC   ---------------------------------------------------------------------------
DR   EMBL; AF494278; AAM96527.1; -; Genomic_DNA.
DR   RefSeq; NP_683792.1; NC_004115.1.
DR   ProteinModelPortal; Q8M9Z4; -.
DR   SMR; Q8M9Z4; -.
DR   GeneID; 860809; -.
DR   GO; GO:0009535; C:chloroplast thylakoid membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR   GO; GO:0045158; F:electron transporter, transferring electrons within cytochrome b6/f complex of photosystem II activity; IEA:InterPro.
DR   GO; GO:0020037; F:heme binding; IEA:InterPro.
DR   GO; GO:0005506; F:iron ion binding; IEA:InterPro.
DR   GO; GO:0016491; F:oxidoreductase activity; IEA:InterPro.
DR   GO; GO:0015979; P:photosynthesis; IEA:UniProtKB-KW.
DR   GO; GO:0022904; P:respiratory electron transport chain; IEA:InterPro.
DR   CDD; cd00284; Cytochrome_b_N; 1.
DR   Gene3D; 1.20.810.10; -; 1.
DR   HAMAP; MF_00633; Cytb6_f_cytb6; 1.
DR   InterPro; IPR005797; Cyt_b/b6_N.
DR   InterPro; IPR023530; Cyt_B6_PetB.
DR   InterPro; IPR027387; Cytb/b6-like_sf.
DR   InterPro; IPR016174; Di-haem_cyt_TM.
DR   PANTHER; PTHR19271:SF8; PTHR19271:SF8; 1.
DR   Pfam; PF00033; Cytochrome_B; 1.
DR   SUPFAM; SSF81342; SSF81342; 1.
DR   PROSITE; PS51002; CYTB_NTER; 1.
PE   3: Inferred from homology;
KW   Chloroplast; Electron transport; Heme; Iron; Membrane; Metal-binding;
KW   Photosynthesis; Plastid; Thylakoid; Transmembrane;
KW   Transmembrane helix; Transport.
FT   CHAIN         1    215       Cytochrome b6.
FT                                /FTId=PRO_0000061785.
FT   TRANSMEM     32     52       Helical. {ECO:0000255|HAMAP-
FT                                Rule:MF_00633}.
FT   TRANSMEM     90    110       Helical. {ECO:0000255|HAMAP-
FT                                Rule:MF_00633}.
FT   TRANSMEM    116    136       Helical. {ECO:0000255|HAMAP-
FT                                Rule:MF_00633}.
FT   TRANSMEM    186    206       Helical. {ECO:0000255|HAMAP-
FT                                Rule:MF_00633}.
FT   METAL        86     86       Iron (heme 2 axial ligand).
FT                                {ECO:0000255|HAMAP-Rule:MF_00633}.
FT   METAL       100    100       Iron (heme 1 axial ligand).
FT                                {ECO:0000255|HAMAP-Rule:MF_00633}.
FT   METAL       187    187       Iron (heme 2 axial ligand).
FT                                {ECO:0000255|HAMAP-Rule:MF_00633}.
FT   METAL       202    202       Iron (heme 1 axial ligand).
FT                                {ECO:0000255|HAMAP-Rule:MF_00633}.
FT   BINDING      35     35       Heme 1 (covalent; via 1 link).
FT                                {ECO:0000255|HAMAP-Rule:MF_00633}.
SQ   SEQUENCE   215 AA;  24231 MW;  2879F90589E0DDFA CRC64;
     MGKVYDWFEE RLEIQAIADD ISSKYVPPHV NIFYCLGGIT FTSFVIQVAS GFAMTFYYRP
     TVTEAFASVQ YIMTEVNFGW LIRSVHRWSA SMMVLMMILH IFRVYLTGGF KKPRELTWVT
     GVILSVLTVS FGVTGYSLPW DQVGYWAVKI VTGVPDAIPV IGSTVVELLR GSVSVGQSTL
     TRFYSLHTFV LPLLTAVFML MHFLMIRKQG ISGPL
//