ID   PETD_CYAPA              Reviewed;         160 AA.
AC   P48122;
DT   01-FEB-1996, integrated into UniProtKB/Swiss-Prot.
DT   01-FEB-1996, sequence version 1.
DT   25-MAY-2022, entry version 88.
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   Cyanophora paradoxa.
OG   Plastid; Cyanelle.
OC   Eukaryota; Glaucocystophyceae; Cyanophoraceae; Cyanophora.
OX   NCBI_TaxID=2762;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=UTEX LB 555 / Pringsheim;
RA   Stirewalt V.L., Michalowski C.B., Loeffelhardt W., Bohnert H.J.,
RA   Bryant D.A.;
RT   "Nucleotide sequence of the cyanelle DNA from Cyanophora paradoxa.";
RL   Plant Mol. Biol. Rep. 13:327-332(1995).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=UTEX LB 555 / Pringsheim;
RA   Loeffelhardt W., Stirewalt V.L., Michalowski C.B., Annarella M.,
RA   Farley J.Y., Schluchter W.M., Chung S., Newmann-Spallart C., Steiner J.M.,
RA   Jakowitsch J., Bohnert H.J., Bryant D.A.;
RT   "The complete sequence of the cyanelle genome of Cyanophora paradoxa: the
RT   genetic complexity of a primitive plastid.";
RL   (In) Schenk H.E.A., Herrmann R., Jeon K.W., Mueller N.E., Schwemmler W.
RL   (eds.);
RL   Eukaryotism and symbiosis, pp.40-48, Springer-Verlag, Heidelberg (1997).
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, cyanelle thylakoid membrane
CC       {ECO:0000250}; 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; U30821; AAA81205.1; -; Genomic_DNA.
DR   PIR; T06862; T06862.
DR   RefSeq; NP_043174.1; NC_001675.1.
DR   AlphaFoldDB; P48122; -.
DR   SMR; P48122; -.
DR   GeneID; 801613; -.
DR   GO; GO:0033115; C:cyanelle 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   Cyanelle; Electron transport; Membrane; Photosynthesis; Plastid; Thylakoid;
KW   Transmembrane; Transmembrane helix; Transport.
FT   CHAIN           1..160
FT                   /note="Cytochrome b6-f complex subunit 4"
FT                   /id="PRO_0000061858"
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;  17470 MW;  E59A0390B32586F6 CRC64;
     MSILKKPDLN DPELRAKLAK GMGHNYYGEP AWPNDLLYIF PVVILGSIAC CGGLAVLDPA
     LIGEPADPFS TPLEILPEWY FFPVFQILRV IPNKLLGVVL MAAVPAGLIA VPFIENVNKF
     QNPFRRPVAS AVFLFGTFVA IWLGIGATFP IDKSLTLGLF