ID CYB6_PELHO Reviewed; 215 AA. AC Q06FN8; DT 06-FEB-2007, integrated into UniProtKB/Swiss-Prot. DT 31-OCT-2006, sequence version 1. DT 02-SEP-2026, entry version 82. DE RecName: Full=Cytochrome b6 {ECO:0000255|HAMAP-Rule:MF_00633}; GN Name=petB-A {ECO:0000255|HAMAP-Rule:MF_00633}; GN and GN Name=petB-B {ECO:0000255|HAMAP-Rule:MF_00633}; OS Pelargonium hortorum (Common geranium) (Pelargonium inquinans x Pelargonium OS zonale). OG Plastid; Chloroplast. OC Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta; OC Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae; OC rosids; malvids; Geraniales; Geraniaceae; Pelargonium. OX NCBI_TaxID=4031; RN [1] RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. RC STRAIN=cv. Ringo White; RX PubMed=16916942; DOI=10.1093/molbev/msl089; RA Chumley T.W., Palmer J.D., Mower J.P., Fourcade H.M., Calie P.J., RA Boore J.L., Jansen R.K.; RT "The complete chloroplast genome sequence of Pelargonium x hortorum: RT organization and evolution of the largest and most highly rearranged RT chloroplast genome of land plants."; RL Mol. Biol. Evol. 23:2175-2190(2006). 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 b; Xref=ChEBI:CHEBI:60344; Evidence={ECO:0000255|HAMAP- CC Rule:MF_00633}; CC Note=Binds 2 heme b groups non-covalently with two histidine residues CC as axial ligands. {ECO:0000255|HAMAP-Rule:MF_00633}; CC -!- COFACTOR: CC Name=heme c; Xref=ChEBI:CHEBI:61717; Evidence={ECO:0000255|HAMAP- CC Rule:MF_00633}; CC Note=Binds one heme group covalently by a single cysteine link with no CC axial amino acid ligand. This heme was named heme ci. 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 and CC the Rieske protein, while the 4 small subunits are PetG, PetL, PetM and CC PetN. The complex functions as a dimer. {ECO:0000255|HAMAP- CC 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 absorbs at CC about 566 nm, and heme 2 (or BL or b562) is low-potential and absorbs CC at about 562 nm. {ECO:0000255|HAMAP-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; DQ897681; ABI17305.1; -; Genomic_DNA. DR EMBL; DQ897681; ABI17335.1; -; Genomic_DNA. DR SMR; Q06FN8; -. DR CDD; cd00284; Cytochrome_b_N; 1. DR FunFam; 1.20.810.10:FF:000001; Cytochrome b6; 1. DR Gene3D; 1.20.810.10; Cytochrome Bc1 Complex, Chain C; 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; IPR048259; Cytochrome_b_N_euk/bac. DR InterPro; IPR016174; Di-haem_cyt_TM. DR PANTHER; PTHR19271; CYTOCHROME B; 1. DR PANTHER; PTHR19271:SF16; CYTOCHROME B; 1. DR Pfam; PF00033; Cytochrome_B; 1. DR PIRSF; PIRSF000032; Cytochrome_b6; 1. DR SUPFAM; SSF81342; Transmembrane di-heme cytochromes; 1. DR NCBIfam; NF002990; PRK03735.1; 1. DR PROSITE; PS51002; CYTB_NTER; 1. DR GO; GO:0009535; C:chloroplast thylakoid membrane; IEA:UniProtKB-SubCell. DR GO; GO:0009055; F:electron transfer activity; IEA:UniProtKB-UniRule. DR GO; GO:0016491; F:oxidoreductase activity; IEA:InterPro. DR GO; GO:0015979; P:photosynthesis; IEA:UniProtKB-UniRule. DR GO; GO:0022904; P:respiratory electron transport chain; IEA:InterPro. DR AlphaFoldDB; Q06FN8; -. PE 3: Inferred from homology; KW Chloroplast; Electron transport; Heme; Iron; Membrane; Metal-binding; KW Photosynthesis; Plastid; Thylakoid; Transmembrane; Transmembrane helix; KW Transport. FT CHAIN 1..215 FT /note="Cytochrome b6" FT /id="PRO_0000275328" FT TRANSMEM 32..52 FT /note="Helical" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00633" FT TRANSMEM 90..110 FT /note="Helical" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00633" FT TRANSMEM 116..136 FT /note="Helical" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00633" FT TRANSMEM 186..206 FT /note="Helical" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00633" FT BINDING 35 FT /ligand="heme c" FT /ligand_id="ChEBI:CHEBI:61717" FT /note="covalent" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00633" FT BINDING 86 FT /ligand="heme b" FT /ligand_id="ChEBI:CHEBI:60344" FT /ligand_label="2" FT /ligand_part="Fe" FT /ligand_part_id="ChEBI:CHEBI:18248" FT /note="axial binding residue" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00633" FT BINDING 100 FT /ligand="heme b" FT /ligand_id="ChEBI:CHEBI:60344" FT /ligand_label="1" FT /ligand_part="Fe" FT /ligand_part_id="ChEBI:CHEBI:18248" FT /note="axial binding residue" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00633" FT BINDING 187 FT /ligand="heme b" FT /ligand_id="ChEBI:CHEBI:60344" FT /ligand_label="2" FT /ligand_part="Fe" FT /ligand_part_id="ChEBI:CHEBI:18248" FT /note="axial binding residue" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00633" FT BINDING 202 FT /ligand="heme b" FT /ligand_id="ChEBI:CHEBI:60344" FT /ligand_label="1" FT /ligand_part="Fe" FT /ligand_part_id="ChEBI:CHEBI:18248" FT /note="axial binding residue" FT /evidence="ECO:0000255|HAMAP-Rule:MF_00633" SQ SEQUENCE 215 AA; 24090 MW; 36539ADE7FD4594B CRC64; MSKVYDWFEE RLEIQAIADD ITSKYVPPHV NIFYCLGGIT LTCFLVQVAT GFAMTFYYRP TVTEAFASVQ YIMTEANFGW LIRSVHRWSA SMMVLMMILH VFRVYLTGGF KKPRELTWVT GVVLAVLTAS FGVTGYSLPR DQIGYWAVKI VTGVPDAIPV IGSPLVELLR GSASVGQSTL TRFYSLHTFV LPLVSAVFML IHFLMIRKQG ISGPL //