ID   CYSI_SHESW              Reviewed;         565 AA.
AC   A1RGD7;
DT   05-FEB-2008, integrated into UniProtKB/Swiss-Prot.
DT   06-FEB-2007, sequence version 1.
DT   02-SEP-2026, entry version 101.
DE   RecName: Full=Sulfite reductase [NADPH] hemoprotein beta-component {ECO:0000255|HAMAP-Rule:MF_01540};
DE            Short=SiR-HP {ECO:0000255|HAMAP-Rule:MF_01540};
DE            Short=SiRHP {ECO:0000255|HAMAP-Rule:MF_01540};
DE            EC=1.8.1.2 {ECO:0000255|HAMAP-Rule:MF_01540};
GN   Name=cysI {ECO:0000255|HAMAP-Rule:MF_01540};
GN   OrderedLocusNames=Sputw3181_0882;
OS   Shewanella sp. (strain W3-18-1).
OC   Bacteria; Pseudomonadati; Pseudomonadota; Gammaproteobacteria;
OC   Alteromonadales; Shewanellaceae; Shewanella.
OX   NCBI_TaxID=351745;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=W3-18-1;
RG   US DOE Joint Genome Institute;
RA   Copeland A., Lucas S., Lapidus A., Barry K., Detter J.C.,
RA   Glavina del Rio T., Hammon N., Israni S., Dalin E., Tice H., Pitluck S.,
RA   Chain P., Malfatti S., Shin M., Vergez L., Schmutz J., Larimer F., Land M.,
RA   Hauser L., Kyrpides N., Lykidis A., Tiedje J., Richardson P.;
RT   "Complete sequence of Shewanella sp. W3-18-1.";
RL   Submitted (DEC-2006) to the EMBL/GenBank/DDBJ databases.
CC   -!- FUNCTION: Component of the sulfite reductase complex that catalyzes the
CC       6-electron reduction of sulfite to sulfide. This is one of several
CC       activities required for the biosynthesis of L-cysteine from sulfate.
CC       {ECO:0000255|HAMAP-Rule:MF_01540}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=hydrogen sulfide + 3 NADP(+) + 3 H2O = sulfite + 3 NADPH + 4
CC         H(+); Xref=Rhea:RHEA:13801, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378,
CC         ChEBI:CHEBI:17359, ChEBI:CHEBI:29919, ChEBI:CHEBI:57783,
CC         ChEBI:CHEBI:58349; EC=1.8.1.2; Evidence={ECO:0000255|HAMAP-
CC         Rule:MF_01540};
CC   -!- COFACTOR:
CC       Name=siroheme; Xref=ChEBI:CHEBI:60052; Evidence={ECO:0000255|HAMAP-
CC         Rule:MF_01540};
CC       Note=Binds 1 siroheme per subunit. {ECO:0000255|HAMAP-Rule:MF_01540};
CC   -!- COFACTOR:
CC       Name=[4Fe-4S] cluster; Xref=ChEBI:CHEBI:49883;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_01540};
CC       Note=Binds 1 [4Fe-4S] cluster per subunit. {ECO:0000255|HAMAP-
CC       Rule:MF_01540};
CC   -!- PATHWAY: Sulfur metabolism; hydrogen sulfide biosynthesis; hydrogen
CC       sulfide from sulfite (NADPH route): step 1/1. {ECO:0000255|HAMAP-
CC       Rule:MF_01540}.
CC   -!- SUBUNIT: Alpha(8)-beta(8). The alpha component is a flavoprotein, the
CC       beta component is a hemoprotein. {ECO:0000255|HAMAP-Rule:MF_01540}.
CC   -!- SIMILARITY: Belongs to the nitrite and sulfite reductase 4Fe-4S domain
CC       family. {ECO:0000255|HAMAP-Rule:MF_01540}.
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DR   EMBL; CP000503; ABM23732.1; -; Genomic_DNA.
DR   RefSeq; WP_011788259.1; NC_008750.1.
DR   AlphaFoldDB; A1RGD7; -.
DR   SMR; A1RGD7; -.
DR   KEGG; shw:Sputw3181_0882; -.
DR   HOGENOM; CLU_001975_3_2_6; -.
DR   UniPathway; UPA00140; UER00207.
DR   GO; GO:0009337; C:sulfite reductase complex (NADPH); IEA:InterPro.
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:0050661; F:NADP binding; IEA:InterPro.
DR   GO; GO:0050311; F:sulfite reductase (ferredoxin) activity; IEA:TreeGrafter.
DR   GO; GO:0004783; F:sulfite reductase (NADPH) activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0008652; P:amino acid biosynthetic process; IEA:InterPro.
DR   GO; GO:0070814; P:hydrogen sulfide biosynthetic process; IEA:UniProtKB-UniRule.
DR   GO; GO:0000103; P:sulfate assimilation; IEA:UniProtKB-UniRule.
DR   FunFam; 3.30.413.10:FF:000003; Sulfite reductase [NADPH] hemoprotein beta-component; 1.
DR   FunFam; 3.30.413.10:FF:000004; Sulfite reductase [NADPH] hemoprotein beta-component; 1.
DR   Gene3D; 3.30.413.10; Sulfite Reductase Hemoprotein, domain 1; 2.
DR   HAMAP; MF_01540; CysI; 1.
DR   InterPro; IPR011786; CysI.
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   NCBIfam; TIGR02041; CysI; 1.
DR   NCBIfam; NF010029; PRK13504.1; 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; Amino-acid biosynthesis; Cysteine biosynthesis; Heme; Iron;
KW   Iron-sulfur; Metal-binding; NADP; Oxidoreductase.
FT   CHAIN           1..565
FT                   /note="Sulfite reductase [NADPH] hemoprotein beta-
FT                   component"
FT                   /id="PRO_1000068774"
FT   BINDING         429
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         435
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         474
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         478
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         478
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:0000255|HAMAP-Rule:MF_01540"
SQ   SEQUENCE   565 AA;  62996 MW;  E36896A650CA30D1 CRC64;
     MSEQKLALNE YLKTDSDYLR GTIKEGLDSS VTGSFSDGDQ QLIKFHGFYQ QDDRDLRNER
     KEQKLEPLYS FMLRARVPGG ICTPQQWLGV DKIASTLTSS NSIRLTTRQT FQYHGIPKRN
     LKTIIQDLDR QALDSIAACG DVNRNVMCNP NPVESKLHEQ AYAVAKKLSD HLLPHTRAYA
     EIWLDEEKLL TTEDETVEPV YGKTYLPRKF KMAVAVPPDN DVDVYTNDLG FIAVAENGEL
     VGFNLTAGGG MGSTHGEVET FPRLADDFGF IKTEDVMKFA EAVMTVQRDW GNRSNRKRSR
     LKYTIVDHGY EKFKAEVEAR AGVKFEPKRD VVIGDRGDRY GWVEGVDGKW HLTLFIESGR
     IKDLPGQTLQ TGLREIAKIH KGDFRMTSNQ NMIIAGVAAE DKATIEGLAR KHGLLGQVLT
     QTRGHSIACV ALPTCPLAMA EAERYFPEFI DHIDALQAKH GISEQAIVVR MTGCPNGCAR
     PFAAEIGLVG KAPGRYNLYL GASFEGTRLN KMHRENIQEA DILAELDTLF GRYAVERDAG
     ETFGNFTVRV GVVKAVIDAA KDFHG
//