ID CYSI_THIRO Reviewed; 559 AA. AC P52673; DT 01-OCT-1996, integrated into UniProtKB/Swiss-Prot. DT 01-OCT-1996, sequence version 1. DT 02-SEP-2026, entry version 105. 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}; OS Thiocapsa roseopersicina. OC Bacteria; Pseudomonadati; Pseudomonadota; Gammaproteobacteria; OC Chromatiales; Chromatiaceae; Thiocapsa. OX NCBI_TaxID=1058; RN [1] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA]. RC STRAIN=DSM 219 / 6311; RX PubMed=8695637; DOI=10.1016/0167-4838(96)00066-0; RA Bruehl A., Haverkamp T., Gisselmann G., Schwenn J.D.; RT "A cDNA clone from Arabidopsis thaliana encoding plastidic RT ferredoxin:sulfite reductase."; RL Biochim. Biophys. Acta 1295:119-124(1996). 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}. 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; Z23169; CAA80688.1; -; Genomic_DNA. DR PIR; S34191; S34191. DR AlphaFoldDB; P52673; -. DR SMR; P52673; -. DR STRING; 1058.SAMN05421783_107103; -. 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 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..559 FT /note="Sulfite reductase [NADPH] hemoprotein beta- FT component" FT /id="PRO_0000199911" FT BINDING 423 FT /ligand="[4Fe-4S] cluster" FT /ligand_id="ChEBI:CHEBI:49883" FT /evidence="ECO:0000255|HAMAP-Rule:MF_01540" FT BINDING 429 FT /ligand="[4Fe-4S] cluster" FT /ligand_id="ChEBI:CHEBI:49883" FT /evidence="ECO:0000255|HAMAP-Rule:MF_01540" FT BINDING 468 FT /ligand="[4Fe-4S] cluster" FT /ligand_id="ChEBI:CHEBI:49883" FT /evidence="ECO:0000255|HAMAP-Rule:MF_01540" FT BINDING 472 FT /ligand="[4Fe-4S] cluster" FT /ligand_id="ChEBI:CHEBI:49883" FT /evidence="ECO:0000255|HAMAP-Rule:MF_01540" FT BINDING 472 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 559 AA; 62272 MW; 6337D0DE9C941C70 CRC64; MSAPIHENER IKARSNCLRG TLRESLADTL TGAISPEDTQ ISKFHGFYQQ DHRDRRQARP EQYLEPYFGF MLRAPLPGGV CTPAQWLAID GMGRELGGGS LRLTTRQSFQ YHGILKRDIA SVIRGINAVM IDSIGGCGDV NRNVLCNPNP VESALHREVY DWAKRISEHL LPRTRAYHEI WLDGEQVGGG EDVEPIYGRT YLPRKFKTAV GVPPHNDVDV YANDLGFAAV ADGSRLIGFN VSAGGTGRNT GIPATFPRLA DVLGFVEPER TLAVAEAVVT TQRHFGDRLD RTQARLKYTI ERMGLDAFRD EVERRAGIRF APARPIGFTD QGDRTAWVRG QDGRWHLTLY IESGRLIDGP GQSSMQGLRE IARIHQGDFR ITPNQNLIVA RVPEPGKSEI EALARKYGLL DKGIALRLNG MSCVALPTCP LAMAEAERYY PDFLAQVERL TRKHGLAEQE IVTRMTGCPN GCARPYLAEL ALVGKGPGRY NLMLGGNGRR YRLNRLYREN LDEAAILAEI DTLLGRYAAC RQPGERFGDY LIRDGIVRPV VNPAEDFHE //