ID   CYSI_MYXXD              Reviewed;         562 AA.
AC   Q1D9W9;
DT   03-NOV-2009, integrated into UniProtKB/Swiss-Prot.
DT   11-JUL-2006, sequence version 1.
DT   03-AUG-2022, entry version 113.
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=MXAN_2334;
OS   Myxococcus xanthus (strain DK1622).
OC   Bacteria; Proteobacteria; Deltaproteobacteria; Myxococcales;
OC   Cystobacterineae; Myxococcaceae; Myxococcus.
OX   NCBI_TaxID=246197;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=DK1622;
RX   PubMed=17015832; DOI=10.1073/pnas.0607335103;
RA   Goldman B.S., Nierman W.C., Kaiser D., Slater S.C., Durkin A.S., Eisen J.,
RA   Ronning C.M., Barbazuk W.B., Blanchard M., Field C., Halling C., Hinkle G.,
RA   Iartchuk O., Kim H.S., Mackenzie C., Madupu R., Miller N., Shvartsbeyn A.,
RA   Sullivan S.A., Vaudin M., Wiegand R., Kaplan H.B.;
RT   "Evolution of sensory complexity recorded in a myxobacterial genome.";
RL   Proc. Natl. Acad. Sci. U.S.A. 103:15200-15205(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; CP000113; ABF92185.1; -; Genomic_DNA.
DR   RefSeq; WP_011552409.1; NC_008095.1.
DR   AlphaFoldDB; Q1D9W9; -.
DR   SMR; Q1D9W9; -.
DR   STRING; 246197.MXAN_2334; -.
DR   EnsemblBacteria; ABF92185; ABF92185; MXAN_2334.
DR   GeneID; 41359720; -.
DR   KEGG; mxa:MXAN_2334; -.
DR   eggNOG; COG0155; Bacteria.
DR   HOGENOM; CLU_001975_3_2_7; -.
DR   OMA; MGMTHGD; -.
DR   OrthoDB; 1588103at2; -.
DR   UniPathway; UPA00140; UER00207.
DR   Proteomes; UP000002402; 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..562
FT                   /note="Sulfite reductase [NADPH] hemoprotein beta-
FT                   component"
FT                   /id="PRO_0000388501"
FT   BINDING         428
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         434
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         473
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         477
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         477
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   562 AA;  62086 MW;  65D27288DDF71F1C CRC64;
     MSHQPKPLSE VEHIKTQSRL LRGSLAESLE DPVTGGLATP DTNLIKFHGS YQQDDRDVRE
     ERRQQKLEPD YSFMLRTRLP GGVCTPAQWL VMDALAREHA NHTLRITTRQ AFQLHGVIKD
     DLRPTIARIN EAMMDTLAAC GDVNRNVLCN PNPVDSRVHE TVYQWAVRIS EHLLPKTRAY
     YEVWLGKEKV AGGEDEPIYG ATYLPRKFKA AVAVPPLNDV DVFAQDLGFI AIIEGDALVG
     FNVSVGGGMG ATHGDAATYP RLADVVGFIP PEQTLAVAEE VVKIHRDFGD RTNRKHARLK
     YVLEERGVPW FTAELEKRLG FPLQPARPFA FEHNGDRFGW TEGHDGRWHL TLHLDSGRVA
     DRPGAPHLTG LREIARIHTG DFRLTANQNL VIAGVTPEAR DAIGALVTAH ALDSFRSASP
     VRRNALACVA LPTCGLAMAE AERYLPTFVG RLEDRLRAHG LQDANLLLRI TGCPNGCARP
     YLAEVGLVGK APGRYNLHLG GDARGQRLSH LYRENIDEDA ILAALEPLFE GYARERQPGE
     GFGDFVVRAG HVPSPAVQPR PS