ID   PETD_ZYGCR              Reviewed;         160 AA.
AC   Q32RG3;
DT   10-JAN-2006, integrated into UniProtKB/Swiss-Prot.
DT   06-DEC-2005, sequence version 1.
DT   25-MAY-2022, entry version 59.
DE   RecName: Full=Cytochrome b6-f complex subunit 4 {ECO:0000255|HAMAP-Rule:MF_01344};
DE   AltName: Full=17 kDa polypeptide {ECO:0000255|HAMAP-Rule:MF_01344};
GN   Name=petD {ECO:0000255|HAMAP-Rule:MF_01344};
OS   Zygnema circumcarinatum (Green alga).
OG   Plastid; Chloroplast.
OC   Eukaryota; Viridiplantae; Streptophyta; Zygnemophyceae; Zygnematophycidae;
OC   Zygnematales; Zygnemataceae; Zygnema.
OX   NCBI_TaxID=35869;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RX   PubMed=16236178; DOI=10.1186/1741-7007-3-22;
RA   Turmel M., Otis C., Lemieux C.;
RT   "The complete chloroplast DNA sequences of the charophycean green algae
RT   Staurastrum and Zygnema reveal that the chloroplast genome underwent
RT   extensive changes during the evolution of the Zygnematales.";
RL   BMC Biol. 3:22-22(2005).
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_01344}.
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 (By similarity). {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Plastid, chloroplast thylakoid membrane
CC       {ECO:0000255|HAMAP-Rule:MF_01344}; Multi-pass membrane protein
CC       {ECO:0000255|HAMAP-Rule:MF_01344}.
CC   -!- SIMILARITY: Belongs to the cytochrome b family. PetD subfamily.
CC       {ECO:0000255|HAMAP-Rule:MF_01344}.
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DR   EMBL; AY958086; AAX45826.1; -; Genomic_DNA.
DR   RefSeq; YP_636563.1; NC_008117.1.
DR   AlphaFoldDB; Q32RG3; -.
DR   SMR; Q32RG3; -.
DR   GeneID; 4108146; -.
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:UniProtKB-UniRule.
DR   GO; GO:0045156; F:electron transporter, transferring electrons within the cyclic electron transport pathway of photosynthesis activity; IEA:InterPro.
DR   GO; GO:0009767; P:photosynthetic electron transport chain; IEA:InterPro.
DR   CDD; cd00290; cytochrome_b_C; 1.
DR   HAMAP; MF_01344; Cytb6_f_subIV; 1.
DR   InterPro; IPR005798; Cyt_b/b6_C.
DR   InterPro; IPR036150; Cyt_b/b6_C_sf.
DR   InterPro; IPR005870; Cyt_b6/f_cplx_suIV.
DR   Pfam; PF00032; Cytochrom_B_C; 1.
DR   PIRSF; PIRSF000033; B6f_17K; 1.
DR   SUPFAM; SSF81648; SSF81648; 1.
DR   TIGRFAMs; TIGR01156; cytb6/f_IV; 1.
DR   PROSITE; PS51003; CYTB_CTER; 1.
PE   3: Inferred from homology;
KW   Chloroplast; Electron transport; Membrane; Photosynthesis; Plastid;
KW   Thylakoid; Transmembrane; Transmembrane helix; Transport.
FT   CHAIN           1..160
FT                   /note="Cytochrome b6-f complex subunit 4"
FT                   /id="PRO_0000061897"
FT   TRANSMEM        36..56
FT                   /note="Helical"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01344"
FT   TRANSMEM        95..115
FT                   /note="Helical"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01344"
FT   TRANSMEM        131..151
FT                   /note="Helical"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01344"
SQ   SEQUENCE   160 AA;  17485 MW;  490E2709FBC31E0F CRC64;
     MGVTKKPDLT DPVLRAKLAK GMGHNYYGEP AWPNDLLYIF PVVIFGTIAC NVGLAVMEPS
     MIGEPANPFA TPLEILPEWY FFPVFQILRT VPNKLLGVLL MAAVPAGLLT VPFLENVNKF
     QNPFRRPVAT TVFLIGTVVS IWLGIGAAMP IDQSLTLGLF