ID   FTRC_CYACA              Reviewed;         111 AA.
AC   Q9TM25;
DT   01-JUN-2001, integrated into UniProtKB/Swiss-Prot.
DT   01-MAY-2000, sequence version 1.
DT   03-AUG-2022, entry version 77.
DE   RecName: Full=Ferredoxin-thioredoxin reductase, catalytic chain;
DE            Short=FTR-C;
DE            EC=1.8.7.2;
DE   AltName: Full=Ferredoxin-thioredoxin reductase subunit B;
DE            Short=FTR-B;
GN   Name=ftrB;
OS   Cyanidium caldarium (Red alga).
OG   Plastid; Chloroplast.
OC   Eukaryota; Rhodophyta; Bangiophyceae; Cyanidiales; Cyanidiaceae; Cyanidium.
OX   NCBI_TaxID=2771;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=RK-1;
RX   PubMed=11040290; DOI=10.1007/s002390010101;
RA   Gloeckner G., Rosenthal A., Valentin K.-U.;
RT   "The structure and gene repertoire of an ancient red algal plastid
RT   genome.";
RL   J. Mol. Evol. 51:382-390(2000).
CC   -!- FUNCTION: Catalytic subunit of the ferredoxin-thioredoxin reductase
CC       (FTR), which catalyzes the two-electron reduction of thioredoxins by
CC       the electrons provided by reduced ferredoxin. {ECO:0000250}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=[thioredoxin]-disulfide + 2 H(+) + 2 reduced [2Fe-2S]-
CC         [ferredoxin] = [thioredoxin]-dithiol + 2 oxidized [2Fe-2S]-
CC         [ferredoxin]; Xref=Rhea:RHEA:42336, Rhea:RHEA-COMP:10000, Rhea:RHEA-
CC         COMP:10001, Rhea:RHEA-COMP:10698, Rhea:RHEA-COMP:10700,
CC         ChEBI:CHEBI:15378, ChEBI:CHEBI:29950, ChEBI:CHEBI:33737,
CC         ChEBI:CHEBI:33738, ChEBI:CHEBI:50058; EC=1.8.7.2;
CC   -!- COFACTOR:
CC       Name=[4Fe-4S] cluster; Xref=ChEBI:CHEBI:49883; Evidence={ECO:0000250};
CC       Note=Binds 1 [4Fe-4S] cluster. {ECO:0000250};
CC   -!- SUBUNIT: Heterodimer of subunit A (variable subunit) and subunit B
CC       (catalytic subunit). Heterodimeric FTR forms a complex with ferredoxin
CC       and thioredoxin (By similarity). {ECO:0000250}.
CC   -!- SUBCELLULAR LOCATION: Plastid, chloroplast.
CC   -!- SIMILARITY: Belongs to the ferredoxin thioredoxin reductase beta
CC       subunit family. {ECO:0000305}.
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DR   EMBL; AF022186; AAF13004.1; -; Genomic_DNA.
DR   RefSeq; NP_045042.1; NC_001840.1.
DR   AlphaFoldDB; Q9TM25; -.
DR   SMR; Q9TM25; -.
DR   PRIDE; Q9TM25; -.
DR   GeneID; 800142; -.
DR   GO; GO:0009507; C:chloroplast; IEA:UniProtKB-SubCell.
DR   GO; GO:0051539; F:4 iron, 4 sulfur cluster binding; ISS:UniProtKB.
DR   GO; GO:0009055; F:electron transfer activity; ISS:UniProtKB.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0016730; F:oxidoreductase activity, acting on iron-sulfur proteins as donors; IEA:InterPro.
DR   Gene3D; 3.90.460.10; -; 1.
DR   InterPro; IPR004209; FTR_bsu.
DR   InterPro; IPR024707; FTR_bsu_Cyanobacter.
DR   InterPro; IPR036644; FTR_bsu_sf.
DR   PANTHER; PTHR35113; PTHR35113; 1.
DR   Pfam; PF02943; FeThRed_B; 1.
DR   PIRSF; PIRSF000260; FTRc; 1.
DR   SUPFAM; SSF57662; SSF57662; 1.
PE   3: Inferred from homology;
KW   4Fe-4S; Chloroplast; Disulfide bond; Iron; Iron-sulfur; Metal-binding;
KW   Oxidoreductase; Plastid; Redox-active center.
FT   CHAIN           1..111
FT                   /note="Ferredoxin-thioredoxin reductase, catalytic chain"
FT                   /id="PRO_0000167671"
FT   ACT_SITE        54
FT                   /note="Nucleophile"
FT                   /evidence="ECO:0000250"
FT   BINDING         52
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000250"
FT   BINDING         71
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000250"
FT   BINDING         73
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000250"
FT   BINDING         82
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000250"
FT   SITE            83
FT                   /note="Increases the nucleophilicity of the active site
FT                   Cys"
FT                   /evidence="ECO:0000250"
FT   DISULFID        54..84
FT                   /note="Redox-active"
FT                   /evidence="ECO:0000250"
SQ   SEQUENCE   111 AA;  12867 MW;  34F9E68E92C8E407 CRC64;
     MRKTPKNLES LHKFAEAYAK LSRTYFCIDQ SITALVIEGL ARHKDDYGAP LCPCRHYENK
     KTEVLAAYWN CPCVPMRERK ECHCMLFLQP SNEFSGESQL ISKDDLQKHL S