ID   SIR_SYNE7               Reviewed;         624 AA.
AC   P30008; Q31SB8;
DT   01-APR-1993, integrated into UniProtKB/Swiss-Prot.
DT   18-APR-2006, sequence version 2.
DT   02-SEP-2026, entry version 145.
DE   RecName: Full=Sulfite reductase [ferredoxin];
DE            EC=1.8.7.1;
GN   Name=sir; OrderedLocusNames=Synpcc7942_0019;
OS   Synechococcus elongatus (strain ATCC 33912 / PCC 7942 / FACHB-805)
OS   (Anacystis nidulans R2).
OC   Bacteria; Bacillati; Cyanobacteriota; Cyanophyceae; Synechococcales;
OC   Synechococcaceae; Synechococcus.
OX   NCBI_TaxID=1140;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=8347657; DOI=10.1016/0005-2728(93)90037-g;
RA   Gisselmann G., Klausmeier P., Schwenn J.D.;
RT   "The ferredoxin:sulphite reductase gene from Synechococcus PCC7942.";
RL   Biochim. Biophys. Acta 1144:102-106(1993).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 33912 / PCC 7942 / FACHB-805;
RG   US DOE Joint Genome Institute;
RA   Copeland A., Lucas S., Lapidus A., Barry K., Detter J.C., Glavina T.,
RA   Hammon N., Israni S., Pitluck S., Schmutz J., Larimer F., Land M.,
RA   Kyrpides N., Lykidis A., Golden S., Richardson P.;
RT   "Complete sequence of chromosome 1 of Synechococcus elongatus PCC 7942.";
RL   Submitted (AUG-2005) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: Catalyzes the reduction of sulfite to sulfide, a step in the
CC       biosynthesis of sulfur-containing amino acids and cofactors.
CC       {ECO:0000250|UniProtKB:P9WJ03}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=hydrogen sulfide + 6 oxidized [2Fe-2S]-[ferredoxin] + 3 H2O =
CC         sulfite + 6 reduced [2Fe-2S]-[ferredoxin] + 7 H(+);
CC         Xref=Rhea:RHEA:23132, Rhea:RHEA-COMP:10000, Rhea:RHEA-COMP:10001,
CC         ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:17359,
CC         ChEBI:CHEBI:29919, ChEBI:CHEBI:33737, ChEBI:CHEBI:33738; EC=1.8.7.1;
CC         Evidence={ECO:0000250|UniProtKB:P9WJ03};
CC   -!- COFACTOR:
CC       Name=siroheme; Xref=ChEBI:CHEBI:60052;
CC       Note=Binds 1 siroheme per subunit.;
CC   -!- COFACTOR:
CC       Name=[4Fe-4S] cluster; Xref=ChEBI:CHEBI:49883;
CC       Note=Binds 1 [4Fe-4S] cluster per subunit.;
CC   -!- SUBUNIT: Monomer.
CC   -!- SIMILARITY: Belongs to the nitrite and sulfite reductase 4Fe-4S domain
CC       family. {ECO:0000305}.
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DR   EMBL; Z11755; CAA77809.1; -; Genomic_DNA.
DR   EMBL; CP000100; ABB56051.1; -; Genomic_DNA.
DR   RefSeq; WP_011377403.1; NC_007604.1.
DR   AlphaFoldDB; P30008; -.
DR   SMR; P30008; -.
DR   STRING; 1140.Synpcc7942_0019; -.
DR   PaxDb; 1140-Synpcc7942_0019; -.
DR   GeneID; 72428828; -.
DR   KEGG; syf:Synpcc7942_0019; -.
DR   eggNOG; COG0155; Bacteria.
DR   HOGENOM; CLU_001975_3_0_3; -.
DR   OrthoDB; 9803707at2; -.
DR   BioCyc; SYNEL:SYNPCC7942_0019-MONOMER; -.
DR   BRENDA; 1.8.7.1; 7781.
DR   Proteomes; UP000889800; Chromosome.
DR   GO; GO:0009337; C:sulfite reductase complex (NADPH); IEA:TreeGrafter.
DR   GO; GO:0051539; F:4 iron, 4 sulfur cluster binding; IEA:InterPro.
DR   GO; GO:0020037; F:heme binding; IEA:InterPro.
DR   GO; GO:0050311; F:sulfite reductase (ferredoxin) activity; IEA:UniProtKB-EC.
DR   GO; GO:0000103; P:sulfate assimilation; IEA:TreeGrafter.
DR   FunFam; 3.30.413.10:FF:000008; Sulfite reductase [ferredoxin], chloroplastic; 1.
DR   FunFam; 3.30.413.10:FF:000014; Sulfite reductase [ferredoxin], chloroplastic; 1.
DR   Gene3D; 3.30.413.10; Sulfite Reductase Hemoprotein, domain 1; 2.
DR   InterPro; IPR005117; NiRdtase/SiRdtase_haem-b_fer.
DR   InterPro; IPR036136; Nit/Sulf_reduc_fer-like_dom_sf.
DR   InterPro; IPR006067; NO2/SO3_Rdtase_4Fe4S_dom.
DR   InterPro; IPR045169; NO2/SO3_Rdtase_4Fe4S_prot.
DR   InterPro; IPR045854; NO2/SO3_Rdtase_4Fe4S_sf.
DR   InterPro; IPR006066; NO2/SO3_Rdtase_FeS/sirohaem_BS.
DR   InterPro; IPR011787; SiR_ferredoxin-dep.
DR   NCBIfam; NF010029; PRK13504.1; 1.
DR   NCBIfam; TIGR02042; sir; 1.
DR   PANTHER; PTHR11493:SF47; SULFITE REDUCTASE [NADPH] SUBUNIT BETA; 1.
DR   PANTHER; PTHR11493; SULFITE REDUCTASE [NADPH] SUBUNIT BETA-RELATED; 1.
DR   Pfam; PF01077; NIR_SIR; 1.
DR   Pfam; PF03460; NIR_SIR_ferr; 2.
DR   PRINTS; PR00397; SIROHAEM.
DR   SUPFAM; SSF56014; Nitrite and sulphite reductase 4Fe-4S domain-like; 2.
DR   SUPFAM; SSF55124; Nitrite/Sulfite reductase N-terminal domain-like; 2.
DR   PROSITE; PS00365; NIR_SIR; 1.
PE   3: Inferred from homology;
KW   4Fe-4S; Heme; Iron; Iron-sulfur; Metal-binding; Oxidoreductase;
KW   Reference proteome; Thioether bond.
FT   CHAIN           1..624
FT                   /note="Sulfite reductase [ferredoxin]"
FT                   /id="PRO_0000199953"
FT   BINDING         446
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000250"
FT   BINDING         452
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000250"
FT   BINDING         491
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000250"
FT   BINDING         495
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000250"
FT   BINDING         495
FT                   /ligand="siroheme"
FT                   /ligand_id="ChEBI:CHEBI:60052"
FT                   /ligand_part="Fe"
FT                   /ligand_part_id="ChEBI:CHEBI:18248"
FT                   /note="axial binding residue"
FT                   /evidence="ECO:0000250"
FT   CROSSLNK        52..137
FT                   /note="3'-(S-cysteinyl)-tyrosine (Tyr-Cys)"
FT                   /evidence="ECO:0000250"
FT   CONFLICT        587
FT                   /note="R -> G (in Ref. 1; CAA77809)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   624 AA;  70131 MW;  E5AABAFD6BBF4539 CRC64;
     MSPTAAPQKL SKVEDLKARS QYLLEPILSQ LQEESTHFNE DGIQILKFHG SYQQDNRDNR
     VKGQEKDFQF MLRLRSPGGY IPPQLYLTLD QLADDYGNGT LRATTRQAFQ LHGILKRDLK
     TVIRRIVENL GSTISACGDV NRNVMAPPAP FRDRPEYEWA RTYANNIADL LTPESGAYYE
     LWLDGEKVLS GEPDPAVLAA RRNPKGRVAD SVEPLYSDRY LPRKFKIAVT VPGDNSIDLF
     TQDIGLVVIG NDRGELEGFN VYVGGGMGRT HNKEETFARL ADPLGFVPAA DIYAAVQAIV
     ATQRDYGDRS NRRHARMKYL IHDWGIAKFK EAVESVFGKA IAPVRELPPF RYRDYLGWHE
     QGDGKWFLGL PITSGRIKDD GNWQLRSALR EIVSRWQLPL LLTGSQDVLI YDVQPGDRAA
     IDKLLRDRGV HTVEAIDSLQ RYAMACPALP TCGLAITESE RALPGLLVRI RRLLEEQGLP
     DEHFVVRMTG CPNGCARPYM AELAFVGSAP NTYQLWLGGS PDQTRLARPF IDRLADGDVE
     TQLRPLFVFF KQSRQAGESF GDFCDRVGFD ALRQFSESYQ HEAAKPRYRV GLRADVHGRL
     KAEADKRGVS LTDLACEAIA AYLR
//