ID   PETD_PROHO              Reviewed;         160 AA.
AC   P28059;
DT   01-AUG-1992, integrated into UniProtKB/Swiss-Prot.
DT   01-AUG-1992, sequence version 1.
DT   25-MAY-2022, entry version 92.
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   Prochlorothrix hollandica.
OC   Bacteria; Cyanobacteria; Pseudanabaenales; Prochlorotrichaceae;
OC   Prochlorothrix.
OX   NCBI_TaxID=1223;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=1623188; DOI=10.1007/bf00023383;
RA   Greer K.L., Golden S.S.;
RT   "Conserved relationship between psbH and petBD genes: presence of a shared
RT   upstream element in Prochlorothrix hollandica.";
RL   Plant Mol. Biol. 19:355-365(1992).
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. {ECO:0000255|HAMAP-
CC       Rule:MF_01344}.
CC   -!- SUBCELLULAR LOCATION: Cellular thylakoid membrane {ECO:0000255|HAMAP-
CC       Rule:MF_01344}; Multi-pass membrane protein {ECO:0000255|HAMAP-
CC       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; X60313; CAA42861.1; -; Genomic_DNA.
DR   PIR; S22472; S22472.
DR   AlphaFoldDB; P28059; -.
DR   SMR; P28059; -.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR   GO; GO:0031676; C:plasma membrane-derived 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: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   Electron transport; Membrane; Photosynthesis; Thylakoid; Transmembrane;
KW   Transmembrane helix; Transport.
FT   CHAIN           1..160
FT                   /note="Cytochrome b6-f complex subunit 4"
FT                   /id="PRO_0000061903"
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        127..147
FT                   /note="Helical"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01344"
SQ   SEQUENCE   160 AA;  17769 MW;  BC2D589FB24E5F8C CRC64;
     MSVLKKPDLT DPVLLEKLAQ NMGHNYYGEP AWPNDLLYTF PVVILGTLAC VVGLAVLDPA
     MVGEPANPFA TPLEILPEWY LYPAFQILRV VPNKLLGILL QTAIPLGLML VPFIENINKF
     QNPFRRPIAM AVFLFGTLVT LWMGVAATLP IDKFFTLGLF