ID   PETD_EUGGR              Reviewed;         173 AA.
AC   Q84TU6;
DT   28-NOV-2003, integrated into UniProtKB/Swiss-Prot.
DT   01-JUN-2003, sequence version 1.
DT   25-MAY-2022, entry version 73.
DE   RecName: Full=Cytochrome b6-f complex subunit 4, chloroplastic;
DE   AltName: Full=17 kDa polypeptide;
DE   Flags: Precursor; Fragment;
GN   Name=petD {ECO:0000303|PubMed:12837550};
OS   Euglena gracilis.
OC   Eukaryota; Discoba; Euglenozoa; Euglenida; Spirocuta; Euglenophyceae;
OC   Euglenales; Euglenaceae; Euglena.
OX   NCBI_TaxID=3039;
RN   [1] {ECO:0000305}
RP   NUCLEOTIDE SEQUENCE [MRNA], PROTEIN SEQUENCE OF 15-63, AND SUBCELLULAR
RP   LOCATION.
RX   PubMed=12837550; DOI=10.1016/s0005-2728(03)00058-6;
RA   Santillan Torres J.L., Atteia A., Claros M.G., Gonzalez-Halphen D.;
RT   "Cytochrome f and subunit IV, two essential components of the
RT   photosynthetic bf complex typically encoded in the chloroplast genome, are
RT   nucleus-encoded in Euglena gracilis.";
RL   Biochim. Biophys. Acta 1604:180-189(2003).
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:0000250|UniProtKB:P49489}.
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).
CC       {ECO:0000250|UniProtKB:P49489}.
CC   -!- SUBCELLULAR LOCATION: Plastid, chloroplast thylakoid membrane
CC       {ECO:0000269|PubMed:12837550}; Multi-pass membrane protein
CC       {ECO:0000269|PubMed:12837550}.
CC   -!- MISCELLANEOUS: This polypeptide is nuclear encoded in Euglena gracilis,
CC       but is chloroplast encoded in other plant species.
CC       {ECO:0000269|PubMed:12837550}.
CC   -!- SIMILARITY: Belongs to the cytochrome b family. PetD subfamily.
CC       {ECO:0000255}.
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DR   EMBL; AY216719; AAO61144.1; -; mRNA.
DR   AlphaFoldDB; Q84TU6; -.
DR   SMR; Q84TU6; -.
DR   GO; GO:0009535; C:chloroplast thylakoid membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0009512; C:cytochrome b6f complex; IDA:UniProtKB.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
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   1: Evidence at protein level;
KW   Chloroplast; Direct protein sequencing; Electron transport; Membrane;
KW   Photosynthesis; Plastid; Thylakoid; Transit peptide; Transmembrane;
KW   Transmembrane helix; Transport.
FT   TRANSIT         <1..14
FT                   /note="Chloroplast"
FT                   /evidence="ECO:0000269|PubMed:12837550"
FT   CHAIN           15..173
FT                   /note="Cytochrome b6-f complex subunit 4, chloroplastic"
FT                   /id="PRO_0000006470"
FT   TRANSMEM        49..69
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        108..128
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   TRANSMEM        144..164
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   CONFLICT        37
FT                   /note="R -> H (in Ref. 1; AA sequence)"
FT                   /evidence="ECO:0000305"
FT   NON_TER         1
FT                   /evidence="ECO:0000303|PubMed:12837550"
SQ   SEQUENCE   173 AA;  18976 MW;  F1E2D10ED06F1CD1 CRC64;
     ESALERRSSS VVMNNVMKKP DLSDPKLRAK LAKGMGRNYY GEPAWPNDLL YMFPVCILGT
     FAAIVGLAVM QPTPTGEPAN PFATPLEILP EWYFFPTFNL LRVIPNKLLG VLSMAAVPAG
     LITVPFIENV NKFQNPFRRP VATSVFLLGT VVAIWLGIGA TLPIDKAISL GFW