ID   CYSI_METNO              Reviewed;         602 AA.
AC   B8IRY2;
DT   03-NOV-2009, integrated into UniProtKB/Swiss-Prot.
DT   03-MAR-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=Mnod_1804;
OS   Methylobacterium nodulans (strain LMG 21967 / CNCM I-2342 / ORS 2060).
OC   Bacteria; Proteobacteria; Alphaproteobacteria; Hyphomicrobiales;
OC   Methylobacteriaceae; Methylobacterium.
OX   NCBI_TaxID=460265;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=LMG 21967 / CNCM I-2342 / ORS 2060;
RG   US DOE Joint Genome Institute;
RA   Lucas S., Copeland A., Lapidus A., Glavina del Rio T., Dalin E., Tice H.,
RA   Bruce D., Goodwin L., Pitluck S., Sims D., Brettin T., Detter J.C., Han C.,
RA   Larimer F., Land M., Hauser L., Kyrpides N., Ivanova N., Marx C.J.,
RA   Richardson P.;
RT   "Complete sequence of chromosome of Methylobacterium nodulans ORS 2060.";
RL   Submitted (JAN-2009) 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=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; CP001349; ACL56794.1; -; Genomic_DNA.
DR   RefSeq; WP_015928486.1; NC_011894.1.
DR   AlphaFoldDB; B8IRY2; -.
DR   SMR; B8IRY2; -.
DR   STRING; 460265.Mnod_1804; -.
DR   EnsemblBacteria; ACL56794; ACL56794; Mnod_1804.
DR   KEGG; mno:Mnod_1804; -.
DR   eggNOG; COG0155; Bacteria.
DR   HOGENOM; CLU_001975_3_2_5; -.
DR   OMA; MGMTHGD; -.
DR   OrthoDB; 1588103at2; -.
DR   UniPathway; UPA00140; UER00207.
DR   Proteomes; UP000008207; 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..602
FT                   /note="Sulfite reductase [NADPH] hemoprotein beta-
FT                   component"
FT                   /id="PRO_0000388496"
FT   REGION          1..24
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   COMPBIAS        1..19
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   BINDING         458
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         464
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         503
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         507
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_01540"
FT   BINDING         507
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   602 AA;  66374 MW;  7999F5883EB40442 CRC64;
     MDDHKTASPP RERSYETPPA ERPITDAEAA RAAALSANEH IKIASGYLRG TLADGLLKHA
     TGAISDDDGQ LVKFHGMYLQ DDRDLRAERT KKKLEKAYSF MIRLRIAGGV VSPKQWLALD
     EIARTYANGT LRATTRQTFQ YHGVIKSNLK RTMQAIDAVL LDTIAACGDV NRNVMAATNP
     AQTGAHKAAY QLAKTISDTL LPKTNAWREI WLDGERVVGG EDEAVEPIYG KTYLPRKFKI
     VVAVPPSNEV DIFAHDLGFI AILDKKNKLK GWNVTVGGGM GMTHGETDTF PRTADVMAFC
     EPEDALKVAE AVMTVQRDWG NRKSRKNARL KYTIERYGLA AFRAEVERRV GRKLQDPKPF
     RFESNGDRYG WVEGEDGRHH LTLYLPSGRI KDVEGGPRYL SGLRRIAEVH QGDFRLTGNQ
     NVIVANVPAD RKSEIDALVA EYGLNLGVTA LRRNSLACVA LPTCGLALAE SERFMPGLLT
     ELEESLAAHG LQDEDITIRM TGCPNGCARP YIAEIGFVGR GPERYNLYLG AAFDGSRLSK
     LYAEDVAAKD IRATLDPLFA AYARDRQPGE RFGDFVIRAG FVAKTINGPD FHDRTGALKA
     VA