ID   CYSI_ANOFW              Reviewed;         571 AA.
AC   B7GJU8;
DT   03-NOV-2009, integrated into UniProtKB/Swiss-Prot.
DT   10-FEB-2009, sequence version 1.
DT   03-AUG-2022, entry version 73.
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}; OrderedLocusNames=Aflv_1596;
OS   Anoxybacillus flavithermus (strain DSM 21510 / WK1).
OC   Bacteria; Firmicutes; Bacilli; Bacillales; Bacillaceae; Anoxybacillus.
OX   NCBI_TaxID=491915;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=DSM 21510 / WK1;
RX   PubMed=19014707; DOI=10.1186/gb-2008-9-11-r161;
RA   Saw J.H., Mountain B.W., Feng L., Omelchenko M.V., Hou S., Saito J.A.,
RA   Stott M.B., Li D., Zhao G., Wu J., Galperin M.Y., Koonin E.V.,
RA   Makarova K.S., Wolf Y.I., Rigden D.J., Dunfield P.F., Wang L., Alam M.;
RT   "Encapsulated in silica: genome, proteome and physiology of the
RT   thermophilic bacterium Anoxybacillus flavithermus WK1.";
RL   Genome Biol. 9:R161.1-R161.16(2008).
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=3 H2O + hydrogen sulfide + 3 NADP(+) = 4 H(+) + 3 NADPH +
CC         sulfite; 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;
CC         Evidence={ECO:0000255|HAMAP-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}.
CC   ---------------------------------------------------------------------------
CC   Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms
CC   Distributed under the Creative Commons Attribution (CC BY 4.0) License
CC   ---------------------------------------------------------------------------
DR   EMBL; CP000922; ACJ33961.1; -; Genomic_DNA.
DR   AlphaFoldDB; B7GJU8; -.
DR   SMR; B7GJU8; -.
DR   STRING; 491915.Aflv_1596; -.
DR   EnsemblBacteria; ACJ33961; ACJ33961; Aflv_1596.
DR   KEGG; afl:Aflv_1596; -.
DR   PATRIC; fig|491915.6.peg.1645; -.
DR   eggNOG; COG0155; Bacteria.
DR   HOGENOM; CLU_001975_3_2_9; -.
DR   OMA; MGMTHGD; -.
DR   OrthoDB; 1588103at2; -.
DR   UniPathway; UPA00140; UER00207.
DR   Proteomes; UP000000742; Chromosome.
DR   GO; GO:0009337; C:sulfite reductase complex (NADPH); IEA:InterPro.
DR   GO; GO:0051539; F:4 iron, 4 sulfur cluster binding; IEA:UniProtKB-KW.
DR   GO; GO:0020037; F:heme binding; IEA:InterPro.
DR   GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR   GO; GO:0050661; F:NADP binding; IEA:InterPro.
DR   GO; GO:0004783; F:sulfite reductase (NADPH) activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0019344; P:cysteine biosynthetic process; IEA:UniProtKB-KW.
DR   GO; GO:0070814; P:hydrogen sulfide biosynthetic process; IEA:UniProtKB-UniRule.
DR   GO; GO:0000103; P:sulfate assimilation; IEA:UniProtKB-UniRule.
DR   Gene3D; 3.30.413.10; -; 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   PANTHER; PTHR11493; PTHR11493; 1.
DR   Pfam; PF01077; NIR_SIR; 2.
DR   Pfam; PF03460; NIR_SIR_ferr; 2.
DR   PRINTS; PR00397; SIROHAEM.
DR   SUPFAM; SSF55124; SSF55124; 2.
DR   SUPFAM; SSF56014; SSF56014; 2.
DR   TIGRFAMs; TIGR02041; CysI; 1.
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; Reference proteome.
FT   CHAIN           1..571
FT                   /note="Sulfite reductase [NADPH] hemoprotein beta-
FT                   component"
FT                   /id="PRO_0000388472"
FT   BINDING         436
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         442
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         481
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         485
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         485
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   571 AA;  64901 MW;  91FDB68EE66B930D CRC64;
     MEKFLLTAPD GPPSDVERIK QESNYLRGTL KETMEDRITA GIPEDDNRLM KFHGSYLQDD
     RDLRAERQKQ KLEPAYQFMI RVRTPGGVAT PEQWLAMDEL ARKYANGTLK LTTRQAFQFH
     GVLKWNMKKT LQAINDALLT TLAACGDVNR NVMCNPNPYQ SEVHAEVYEW AKRLSDHLLP
     QTRAYYEIWL DEEKVADTPD VEQEPIYGAL YLPRKFKIGI AVPPSNDVDV FSQDLGFIAI
     VEHGKLAGFN VAIGGGMGMT HGDRTTYPQL AKVIGFCKPE QVIDVAEKVV TIQRDYGNRS
     VRKHARFKYT IDRLGLDAIK AELERRLGWE LEEARPYRFE HNGDRYGWVE GVNGTWHFTL
     FIEGGRVKDT DDYPLMTGLR EIAKVHTGDF RLTANQNLVI ANVPSEKKEE MDALIQQYKL
     TDGKHYSALR RNSLACVALP TCGLAMAEAE RYLPTLIDKI EEIVEENGLR DEEITIRMTG
     CPNGCARHVL GEIAFIGKSV GKYNMYLGAA FDGSRLGKLY RENIGEKEIL SELRMLLSRY
     AKERFDGERF GDFVIRAGIV KEVTDGTNFH D