ID   CYSI_ECOUT              Reviewed;         570 AA.
AC   Q1R7T5;
DT   05-FEB-2008, integrated into UniProtKB/Swiss-Prot.
DT   16-MAY-2006, sequence version 1.
DT   03-AUG-2022, entry version 90.
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=UTI89_C3127;
OS   Escherichia coli (strain UTI89 / UPEC).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Enterobacteriaceae; Escherichia.
OX   NCBI_TaxID=364106;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=UTI89 / UPEC;
RX   PubMed=16585510; DOI=10.1073/pnas.0600938103;
RA   Chen S.L., Hung C.-S., Xu J., Reigstad C.S., Magrini V., Sabo A.,
RA   Blasiar D., Bieri T., Meyer R.R., Ozersky P., Armstrong J.R., Fulton R.S.,
RA   Latreille J.P., Spieth J., Hooton T.M., Mardis E.R., Hultgren S.J.,
RA   Gordon J.I.;
RT   "Identification of genes subject to positive selection in uropathogenic
RT   strains of Escherichia coli: a comparative genomics approach.";
RL   Proc. Natl. Acad. Sci. U.S.A. 103:5977-5982(2006).
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}.
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DR   EMBL; CP000243; ABE08579.1; -; Genomic_DNA.
DR   RefSeq; WP_001290708.1; NC_007946.1.
DR   AlphaFoldDB; Q1R7T5; -.
DR   SMR; Q1R7T5; -.
DR   EnsemblBacteria; ABE08579; ABE08579; UTI89_C3127.
DR   KEGG; eci:UTI89_C3127; -.
DR   HOGENOM; CLU_001975_3_2_6; -.
DR   OMA; MGMTHGD; -.
DR   UniPathway; UPA00140; UER00207.
DR   Proteomes; UP000001952; 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.
FT   CHAIN           1..570
FT                   /note="Sulfite reductase [NADPH] hemoprotein beta-
FT                   component"
FT                   /id="PRO_1000068762"
FT   BINDING         434
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         440
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         479
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         483
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         483
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   570 AA;  63988 MW;  5AF5F1FC980A433F CRC64;
     MSEKHPGPLV VEGKLTDAER MKLESNYLRG TIAEDLNDGL TGGFKGDNFL LIRFHGMYQQ
     DDRDIRAERA EQKLEPRHAM LLRCRLPGGV ITTKQWQAID KFAGENTIYG SIRLTNRQTF
     QFHGILKKNV KPVHQMLHSV GLDALATAND MNRNVLCTSN PYESQLHAEA YEWAKKISEH
     LLPRTRAYAE IWLDQEKVAT TDEEPILGQT YLPRKFKTTV VIPPQNDIDL HANDMNFVAI
     AENGKLVGFN LLVGGGLSIE HGNKKTYART ASEFGYLPLE HTLAVAEAVV TTQRDWGNRT
     DRKNAKTKYT LERVGVETFK AEVERRAGIK FEPIRPYEFT GRGDRIGWVK GIDDNWHLTL
     FIENGRILDY PGRPLKTGLL EIAKIHKGDF RITANQNLII AGVPESEKAK IEKIAKESGL
     MNAVTPQREN SMACVSFPTC PLAMAEAERF LPSFIDNIDN LMAKHGVSDE HIVMRVTGCP
     NGCGRAMLAE VGLVGKAPGR YNLHLGGNRI GTRIPRMYKE NITEPEILAS LDELIGRWAK
     EREVGEGFGD FTVRAGIIRP VLDPARDLWD