ID A0A1P8D674_9FLOR Unreviewed; 215 AA. AC A0A1P8D674; DT 12-APR-2017, integrated into UniProtKB/TrEMBL. DT 12-APR-2017, sequence version 1. DT 27-SEP-2017, entry version 4. DE RecName: Full=Cytochrome b6 {ECO:0000256|HAMAP-Rule:MF_00633}; GN Name=petB {ECO:0000256|HAMAP-Rule:MF_00633, GN ECO:0000313|EMBL:APR74306.1}; OS Gracilaria firma. OG Plastid {ECO:0000313|EMBL:APR74306.1}. OC Eukaryota; Rhodophyta; Florideophyceae; Gracilariales; Gracilariaceae; OC Gracilaria. OX NCBI_TaxID=330876 {ECO:0000313|EMBL:APR74306.1}; RN [1] {ECO:0000313|EMBL:APR74306.1} RP NUCLEOTIDE SEQUENCE. RA Florea S., Webb J.S., Jaromczyk J., Schardl C.L.; RL Submitted (JUL-2016) to the EMBL/GenBank/DDBJ databases. RN [2] {ECO:0000313|EMBL:APR74306.1} RP NUCLEOTIDE SEQUENCE. RX PubMed=28061748; DOI=10.1186/s12864-016-3453-0; RA Ng P.K., Lin S.M., Lim P.E., Liu L.C., Chen C.M., Pai T.W.; RT "Complete chloroplast genome of Gracilaria firma (Gracilariaceae, RT Rhodophyta), with discussion on the use of chloroplast phylogenomics RT in the subclass Rhodymeniophycidae."; RL BMC Genomics 18:40-40(2017). 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:0000256|HAMAP-Rule:MF_00633}. CC -!- COFACTOR: CC Name=heme; Xref=ChEBI:CHEBI:30413; Evidence={ECO:0000256|HAMAP- CC Rule:MF_00633, ECO:0000256|PIRSR:PIRSR000032-50}; 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:0000256|HAMAP-Rule:MF_00633, ECO:0000256|PIRSR:PIRSR000032- CC 50}; 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:0000256|HAMAP-Rule:MF_00633}. CC -!- SUBCELLULAR LOCATION: Cellular thylakoid membrane CC {ECO:0000256|HAMAP-Rule:MF_00633}; Multi-pass membrane protein CC {ECO:0000256|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:0000256|HAMAP- CC Rule:MF_00633}. CC -!- SIMILARITY: Belongs to the cytochrome b family. PetB subfamily. CC {ECO:0000256|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; KX601051; APR74306.1; -; Genomic_DNA. DR GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW. DR GO; GO:0009536; C:plastid; IEA:UniProtKB-KW. DR GO; GO:0042651; C:thylakoid membrane; IEA:UniProtKB-SubCell. DR GO; GO:0045158; F:electron transporter, transferring electrons within cytochrome b6/f complex of photosystem II activity; IEA:UniProtKB-UniRule. 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-UniRule. 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. DR InterPro; IPR016174; Di-haem_cyt_TM. DR Pfam; PF00033; Cytochrome_B; 1. DR PIRSF; PIRSF000032; Cytochrome_b6; 1. DR SUPFAM; SSF81342; SSF81342; 1. DR PROSITE; PS51002; CYTB_NTER; 1. PE 3: Inferred from homology; KW Electron transport {ECO:0000256|HAMAP-Rule:MF_00633}; KW Heme {ECO:0000256|HAMAP-Rule:MF_00633, ECO:0000256|PIRSR:PIRSR000032- KW 50}; KW Iron {ECO:0000256|HAMAP-Rule:MF_00633, ECO:0000256|PIRSR:PIRSR000032- KW 50}; KW Membrane {ECO:0000256|HAMAP-Rule:MF_00633, ECO:0000256|SAM:Phobius}; KW Metal-binding {ECO:0000256|HAMAP-Rule:MF_00633, KW ECO:0000256|PIRSR:PIRSR000032-50}; KW Photosynthesis {ECO:0000256|HAMAP-Rule:MF_00633}; KW Plastid {ECO:0000313|EMBL:APR74306.1}; KW Transmembrane {ECO:0000256|HAMAP-Rule:MF_00633, KW ECO:0000256|SAM:Phobius}; KW Transmembrane helix {ECO:0000256|HAMAP-Rule:MF_00633, KW ECO:0000256|SAM:Phobius}; KW Transport {ECO:0000256|HAMAP-Rule:MF_00633}. FT TRANSMEM 32 58 Helical. {ECO:0000256|SAM:Phobius}. FT TRANSMEM 88 106 Helical. {ECO:0000256|SAM:Phobius}. FT TRANSMEM 118 138 Helical. {ECO:0000256|SAM:Phobius}. FT TRANSMEM 184 206 Helical. {ECO:0000256|SAM:Phobius}. FT DOMAIN 4 215 CYTB_NTER. {ECO:0000259|PROSITE:PS51002}. FT METAL 86 86 Iron (heme 2 axial ligand). FT {ECO:0000256|HAMAP-Rule:MF_00633}. FT METAL 100 100 Iron (heme 1 axial ligand). FT {ECO:0000256|HAMAP-Rule:MF_00633}. FT METAL 187 187 Iron (heme 2 axial ligand). FT {ECO:0000256|HAMAP-Rule:MF_00633}. FT METAL 202 202 Iron (heme 1 axial ligand). FT {ECO:0000256|HAMAP-Rule:MF_00633}. FT BINDING 35 35 Heme 1 (covalent; via 1 link). FT {ECO:0000256|HAMAP-Rule:MF_00633, FT ECO:0000256|PIRSR:PIRSR000032-50}. SQ SEQUENCE 215 AA; 24180 MW; 116A1B837B522574 CRC64; MGKVYDWFEE RLEIQAIADD ITSKYVPPHV NIFYCIGGIV FTSFLIQVAS GFAMTFYYRP TVAEAFSSVE YIMTDVNFGW LIRSIHRWSA SMMVLMLILH MFRVYLTGGF KKPRELTWVT GVILAVLTVS FGVTGYSLPW DQIGYWAVKI VTGVPEAIPL VGASIVELLR GGVSVGQGTL TRFYSLHTFV LPLLTAVFML MHFLMIRKQG ISGPL //