ID   A0A2I6QD76_9LAMI        Unreviewed;       215 AA.
AC   A0A2I6QD76;
DT   28-MAR-2018, integrated into UniProtKB/TrEMBL.
DT   28-MAR-2018, sequence version 1.
DT   29-MAY-2024, entry version 21.
DE   RecName: Full=Cytochrome b6 {ECO:0000256|ARBA:ARBA00035697, ECO:0000256|HAMAP-Rule:MF_00633};
GN   Name=petB {ECO:0000256|HAMAP-Rule:MF_00633,
GN   ECO:0000313|EMBL:AUN28332.1};
GN   ORFNames=BK572_Gau_0071 {ECO:0000313|EMBL:AUN28332.1};
OS   Genlisea aurea.
OG   Plastid; Chloroplast {ECO:0000313|EMBL:AUN28332.1}.
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   asterids; lamiids; Lamiales; Lentibulariaceae; Genlisea.
OX   NCBI_TaxID=192259 {ECO:0000313|EMBL:AUN28332.1};
RN   [1] {ECO:0000313|EMBL:AUN28332.1}
RP   NUCLEOTIDE SEQUENCE.
RX   PubMed=29293597; DOI=10.1371/journal.pone.0190321;
RA   Silva S.R., Michael T.P., Meer E.J., Pinheiro D.G., Varani A.M.,
RA   Miranda V.F.O.;
RT   "Comparative genomic analysis of Genlisea (corkscrew plants-
RT   Lentibulariaceae) chloroplast genomes reveals an increasing loss of the ndh
RT   genes.";
RL   PLoS ONE 13:e0190321-e0190321(2018).
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|ARBA:ARBA00003068, ECO:0000256|HAMAP-Rule:MF_00633,
CC       ECO:0000256|RuleBase:RU003291}.
CC   -!- COFACTOR:
CC       Name=heme b; Xref=ChEBI:CHEBI:60344;
CC         Evidence={ECO:0000256|HAMAP-Rule:MF_00633,
CC         ECO:0000256|RuleBase:RU003291};
CC       Note=Binds 2 heme b groups non-covalently with two histidine residues
CC       as axial ligands. {ECO:0000256|HAMAP-Rule:MF_00633,
CC       ECO:0000256|RuleBase:RU003291};
CC   -!- COFACTOR:
CC       Name=heme c; Xref=ChEBI:CHEBI:61717;
CC         Evidence={ECO:0000256|HAMAP-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:0000256|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:0000256|ARBA:ARBA00025834,
CC       ECO:0000256|HAMAP-Rule:MF_00633, ECO:0000256|RuleBase:RU003291}.
CC   -!- SUBCELLULAR LOCATION: Membrane {ECO:0000256|ARBA:ARBA00004141}; Multi-
CC       pass membrane protein {ECO:0000256|ARBA:ARBA00004141}. Plastid,
CC       chloroplast thylakoid membrane {ECO:0000256|HAMAP-Rule:MF_00633,
CC       ECO:0000256|RuleBase:RU003291}; Multi-pass membrane protein
CC       {ECO:0000256|HAMAP-Rule:MF_00633, ECO:0000256|RuleBase:RU003291}.
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:0000256|HAMAP-Rule:MF_00633}.
CC   -!- SIMILARITY: Belongs to the cytochrome b family. PetB subfamily.
CC       {ECO:0000256|HAMAP-Rule:MF_00633, ECO:0000256|RuleBase:RU003291}.
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DR   EMBL; MF593121; AUN28332.1; -; Genomic_DNA.
DR   AlphaFoldDB; A0A2I6QD76; -.
DR   GO; GO:0009535; C:chloroplast thylakoid membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0005750; C:mitochondrial respiratory chain complex III; IEA:TreeGrafter.
DR   GO; GO:0045158; F:electron transporter, transferring electrons within cytochrome b6/f complex of photosystem II activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0008121; F:ubiquinol-cytochrome-c reductase activity; IEA:TreeGrafter.
DR   GO; GO:0006122; P:mitochondrial electron transport, ubiquinol to cytochrome c; IEA:TreeGrafter.
DR   GO; GO:0015979; P:photosynthesis; IEA:UniProtKB-UniRule.
DR   CDD; cd00284; Cytochrome_b_N; 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   PROSITE; PS51002; CYTB_NTER; 1.
PE   3: Inferred from homology;
KW   Chloroplast {ECO:0000256|RuleBase:RU003291, ECO:0000313|EMBL:AUN28332.1};
KW   Electron transport {ECO:0000256|HAMAP-Rule:MF_00633,
KW   ECO:0000256|RuleBase:RU003291};
KW   Heme {ECO:0000256|HAMAP-Rule:MF_00633, ECO:0000256|RuleBase:RU003291};
KW   Iron {ECO:0000256|HAMAP-Rule:MF_00633, ECO:0000256|RuleBase:RU003291};
KW   Membrane {ECO:0000256|HAMAP-Rule:MF_00633, ECO:0000256|SAM:Phobius};
KW   Metal-binding {ECO:0000256|HAMAP-Rule:MF_00633,
KW   ECO:0000256|RuleBase:RU003291};
KW   Photosynthesis {ECO:0000256|ARBA:ARBA00022531, ECO:0000256|HAMAP-
KW   Rule:MF_00633}; Plastid {ECO:0000313|EMBL:AUN28332.1};
KW   Thylakoid {ECO:0000256|HAMAP-Rule:MF_00633, ECO:0000256|RuleBase:RU003291};
KW   Transmembrane {ECO:0000256|HAMAP-Rule:MF_00633,
KW   ECO:0000256|RuleBase:RU003291};
KW   Transmembrane helix {ECO:0000256|HAMAP-Rule:MF_00633,
KW   ECO:0000256|SAM:Phobius};
KW   Transport {ECO:0000256|HAMAP-Rule:MF_00633, ECO:0000256|RuleBase:RU003291}.
FT   TRANSMEM        32..58
FT                   /note="Helical"
FT                   /evidence="ECO:0000256|SAM:Phobius"
FT   TRANSMEM        88..106
FT                   /note="Helical"
FT                   /evidence="ECO:0000256|SAM:Phobius"
FT   TRANSMEM        118..138
FT                   /note="Helical"
FT                   /evidence="ECO:0000256|SAM:Phobius"
FT   TRANSMEM        184..203
FT                   /note="Helical"
FT                   /evidence="ECO:0000256|SAM:Phobius"
FT   DOMAIN          4..215
FT                   /note="Cytochrome b/b6 N-terminal region profile"
FT                   /evidence="ECO:0000259|PROSITE:PS51002"
FT   BINDING         35
FT                   /ligand="heme c"
FT                   /ligand_id="ChEBI:CHEBI:61717"
FT                   /note="covalent"
FT                   /evidence="ECO:0000256|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:0000256|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:0000256|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:0000256|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:0000256|HAMAP-Rule:MF_00633"
SQ   SEQUENCE   215 AA;  24181 MW;  E4E9925F88550B32 CRC64;
     MSKVYDWFEE RLEIQTIADD ITSKYVPPHV NIFYCLGGIT LTCFLVQVAT GFAMTFYYRP
     TVTEAFSSVQ YIMTEANFGW LIRSVHRWSA SMMVLMMILH VFRVYLTGGF KKPRELTWVT
     GVVLAVLTAS FGVTGYSLPR DQIGYWAVKI VTGVPEAIPV IGSPLVELLR GSASVGQSTL
     TRFYSLHTFV LPLLTAVFML MHFPMIRKQG ISGPL
//