ID CYSI_ECOLI Reviewed; 570 AA. AC P17846; Q2MA66; DT 01-AUG-1990, integrated into UniProtKB/Swiss-Prot. DT 23-JAN-2007, sequence version 4. DT 02-SEP-2026, entry version 204. 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; OrderedLocusNames=b2763, JW2733; OS Escherichia coli (strain K12). OC Bacteria; Pseudomonadati; Pseudomonadota; Gammaproteobacteria; OC Enterobacterales; Enterobacteriaceae; Escherichia. OX NCBI_TaxID=83333; RN [1] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA], AND PARTIAL PROTEIN SEQUENCE. RC STRAIN=B; RX PubMed=2670946; DOI=10.1016/s0021-9258(19)84893-7; RA Ostrowski J., Wu J.-Y., Rueger D.C., Miller B.E., Siegel L.M., RA Kredich N.M.; RT "Characterization of the cysJIH regions of Salmonella typhimurium and RT Escherichia coli B. DNA sequences of cysI and cysH and a model for the RT siroheme-Fe4S4 active center of sulfite reductase hemoprotein based on RT amino acid homology with spinach nitrite reductase."; RL J. Biol. Chem. 264:15726-15737(1989). RN [2] RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. RC STRAIN=K12 / MG1655 / ATCC 47076; RX PubMed=9278503; DOI=10.1126/science.277.5331.1453; RA Blattner F.R., Plunkett G. III, Bloch C.A., Perna N.T., Burland V., RA Riley M., Collado-Vides J., Glasner J.D., Rode C.K., Mayhew G.F., RA Gregor J., Davis N.W., Kirkpatrick H.A., Goeden M.A., Rose D.J., Mau B., RA Shao Y.; RT "The complete genome sequence of Escherichia coli K-12."; RL Science 277:1453-1462(1997). RN [3] RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA]. RC STRAIN=K12 / W3110 / ATCC 27325 / DSM 5911; RX PubMed=16738553; DOI=10.1038/msb4100049; RA Hayashi K., Morooka N., Yamamoto Y., Fujita K., Isono K., Choi S., RA Ohtsubo E., Baba T., Wanner B.L., Mori H., Horiuchi T.; RT "Highly accurate genome sequences of Escherichia coli K-12 strains MG1655 RT and W3110."; RL Mol. Syst. Biol. 2:E1-E5(2006). RN [4] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 344-570. RC STRAIN=K12; RX PubMed=2005873; DOI=10.1007/bf00269864; RA Krone F.A., Westphal G., Schwenn J.D.; RT "Characterisation of the gene cysH and of its product phospho- RT adenylylsulphate reductase from Escherichia coli."; RL Mol. Gen. Genet. 225:314-319(1991). RN [5] RP PROTEIN SEQUENCE OF 2-13. RC STRAIN=K12 / EMG2; RX PubMed=9298646; DOI=10.1002/elps.1150180807; RA Link A.J., Robison K., Church G.M.; RT "Comparing the predicted and observed properties of proteins encoded in the RT genome of Escherichia coli K-12."; RL Electrophoresis 18:1259-1313(1997). RN [6] RP X-RAY CRYSTALLOGRAPHY (1.6 ANGSTROMS) OF 74-570 IN COMPLEX WITH HEME AND RP IRON-SULFUR (4FE-4S), AND COFACTOR. RX PubMed=7569952; DOI=10.1126/science.270.5233.59; RA Crane B.R., Siegel L.M., Getzoff E.D.; RT "Sulfite reductase structure at 1.6 A: evolution and catalysis for RT reduction of inorganic anions."; RL Science 270:59-67(1995). RN [7] RP X-RAY CRYSTALLOGRAPHY (1.75 ANGSTROMS) OF 74-570 IN COMPLEX WITH HEME AND RP IRON-SULFUR (4FE-4S), AND COFACTOR. RX PubMed=9315848; DOI=10.1021/bi971065q; RA Crane B.R., Siegel L.M., Getzoff E.D.; RT "Structures of the siroheme- and Fe4S4-containing active center of sulfite RT reductase in different states of oxidation: heme activation via reduction- RT gated exogenous ligand exchange."; RL Biochemistry 36:12101-12119(1997). 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, ECO:0000269|PubMed:7569952, CC ECO:0000269|PubMed:9315848}; CC Note=Binds 1 siroheme per subunit. {ECO:0000255|HAMAP-Rule:MF_01540, CC ECO:0000269|PubMed:7569952, ECO:0000269|PubMed:9315848}; CC -!- COFACTOR: CC Name=[4Fe-4S] cluster; Xref=ChEBI:CHEBI:49883; CC Evidence={ECO:0000255|HAMAP-Rule:MF_01540, CC ECO:0000269|PubMed:7569952, ECO:0000269|PubMed:9315848}; CC Note=Binds 1 [4Fe-4S] cluster per subunit. {ECO:0000255|HAMAP- CC Rule:MF_01540, ECO:0000269|PubMed:7569952, ECO:0000269|PubMed:9315848}; 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:0000305}. CC -!- SEQUENCE CAUTION: CC Sequence=AAA23651.1; Type=Erroneous initiation; Evidence={ECO:0000305}; CC Sequence=CAA68816.1; Type=Erroneous initiation; Evidence={ECO:0000305}; 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; M23008; AAA23651.1; ALT_INIT; Genomic_DNA. DR EMBL; U29579; AAA69273.1; -; Genomic_DNA. DR EMBL; U00096; AAC75805.1; -; Genomic_DNA. DR EMBL; AP009048; BAE76840.1; -; Genomic_DNA. DR EMBL; Y07525; CAA68816.1; ALT_INIT; Genomic_DNA. DR PIR; G65057; RDECSH. DR RefSeq; NP_417243.1; NC_000913.3. DR RefSeq; WP_001290679.1; NZ_CP009789.1. DR PDB; 1AOP; X-ray; 1.60 A; A=74-570. DR PDB; 2AOP; X-ray; 1.75 A; A=74-570. DR PDB; 2GEP; X-ray; 1.90 A; A=74-570. DR PDB; 3AOP; X-ray; 2.10 A; A=74-570. DR PDB; 3GEO; X-ray; 2.10 A; A=74-570. DR PDB; 4AOP; X-ray; 1.80 A; A=74-570. DR PDB; 4G38; X-ray; 1.56 A; A=1-570. DR PDB; 4G39; X-ray; 2.40 A; A=1-570. DR PDB; 4GEP; X-ray; 2.00 A; A=74-570. DR PDB; 4HTR; X-ray; 1.60 A; A=64-570. DR PDB; 5AOP; X-ray; 2.20 A; A=74-570. DR PDB; 5GEP; X-ray; 2.10 A; A=74-570. DR PDB; 6C3M; X-ray; 1.50 A; A=1-570. DR PDB; 6C3X; X-ray; 1.54 A; A=1-570. DR PDB; 6C3Y; X-ray; 1.54 A; A=1-570. DR PDB; 6C3Z; X-ray; 1.68 A; A=1-570. DR PDB; 6GEP; X-ray; 1.80 A; A=74-570. DR PDB; 7GEP; X-ray; 2.40 A; A=74-570. DR PDB; 8GEP; X-ray; 2.20 A; A=74-570. DR PDB; 9C91; EM; 2.78 A; B=1-570. DR AlphaFoldDB; P17846; -. DR SASBDB; P17846; -. DR SMR; P17846; -. DR BioGRID; 4262276; 173. DR ComplexPortal; CPX-5629; Sulfite reductase [NADPH] complex. DR DIP; DIP-9380N; -. DR FunCoup; P17846; 322. DR IntAct; P17846; 11. DR STRING; 511145.b2763; -. DR DrugBank; DB02832; Siroheme. DR jPOST; P17846; -. DR PaxDb; 511145-b2763; -. DR EnsemblBacteria; AAC75805; AAC75805; b2763. DR GeneID; 947231; -. DR KEGG; ecj:JW2733; -. DR KEGG; eco:b2763; -. DR KEGG; ecoc:C3026_15185; -. DR PATRIC; fig|1411691.4.peg.3974; -. DR EchoBASE; EB0187; -. DR eggNOG; COG0155; Bacteria. DR HOGENOM; CLU_001975_3_2_6; -. DR InParanoid; P17846; -. DR OMA; IKISGCM; -. DR OrthoDB; 3189055at2; -. DR PhylomeDB; P17846; -. DR BioCyc; EcoCyc:BETACOMP-MONOMER; -. DR BioCyc; MetaCyc:BETACOMP-MONOMER; -. DR BRENDA; 1.8.1.2; 2026. DR UniPathway; UPA00140; UER00207. DR EvolutionaryTrace; P17846; -. DR PRO; PR:P17846; -. DR Proteomes; UP000000625; Chromosome. DR AbasyAtlas; P17846; -. DR GO; GO:0009337; C:sulfite reductase complex (NADPH); IDA:EcoCyc. DR GO; GO:0051539; F:4 iron, 4 sulfur cluster binding; IDA:EcoCyc. DR GO; GO:0020037; F:heme binding; IDA:EcoCyc. DR GO; GO:0050661; F:NADP binding; IEA:InterPro. DR GO; GO:0004783; F:sulfite reductase (NADPH) activity; IEA:UniProtKB-UniRule. DR GO; GO:0070814; P:hydrogen sulfide biosynthetic process; IEA:UniProtKB-UniRule. DR GO; GO:0019344; P:L-cysteine biosynthetic process; NAS:ComplexPortal. DR GO; GO:0000103; P:sulfate assimilation; IDA:ComplexPortal. DR FunFam; 3.30.413.10:FF:000003; Sulfite reductase [NADPH] hemoprotein beta-component; 1. DR FunFam; 3.30.413.10:FF:000004; 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. DR PDBsum; 1AOP; -. DR PDBsum; 2AOP; -. DR PDBsum; 2GEP; -. DR PDBsum; 3AOP; -. DR PDBsum; 3GEO; -. DR PDBsum; 4AOP; -. DR PDBsum; 4G38; -. DR PDBsum; 4G39; -. DR PDBsum; 4GEP; -. DR PDBsum; 4HTR; -. DR PDBsum; 5AOP; -. DR PDBsum; 5GEP; -. DR PDBsum; 6C3M; -. DR PDBsum; 6C3X; -. DR PDBsum; 6C3Y; -. DR PDBsum; 6C3Z; -. DR PDBsum; 6GEP; -. DR PDBsum; 7GEP; -. DR PDBsum; 8GEP; -. DR PDBsum; 9C91; -. PE 1: Evidence at protein level; KW 3D-structure; 4Fe-4S; Amino-acid biosynthesis; Cysteine biosynthesis; KW Direct protein sequencing; Heme; Iron; Iron-sulfur; Metal-binding; NADP; KW Oxidoreductase; Reference proteome. FT INIT_MET 1 FT /note="Removed" FT /evidence="ECO:0000269|PubMed:9298646" FT CHAIN 2..570 FT /note="Sulfite reductase [NADPH] hemoprotein beta- FT component" FT /id="PRO_0000199896" FT BINDING 434 FT /ligand="[4Fe-4S] cluster" FT /ligand_id="ChEBI:CHEBI:49883" FT /evidence="ECO:0000269|PubMed:7569952, FT ECO:0000269|PubMed:9315848" FT BINDING 440 FT /ligand="[4Fe-4S] cluster" FT /ligand_id="ChEBI:CHEBI:49883" FT /evidence="ECO:0000269|PubMed:7569952, FT ECO:0000269|PubMed:9315848" FT BINDING 479 FT /ligand="[4Fe-4S] cluster" FT /ligand_id="ChEBI:CHEBI:49883" FT /evidence="ECO:0000269|PubMed:7569952, FT ECO:0000269|PubMed:9315848" FT BINDING 483 FT /ligand="[4Fe-4S] cluster" FT /ligand_id="ChEBI:CHEBI:49883" FT /evidence="ECO:0000269|PubMed:7569952, FT ECO:0000269|PubMed:9315848" 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:0000269|PubMed:7569952, FT ECO:0000269|PubMed:9315848" FT CONFLICT 23 FT /note="H -> L (in Ref. 1; AAA23651)" FT /evidence="ECO:0000305" FT HELIX 14..16 FT /evidence="ECO:0007829|PDB:9C91" FT HELIX 17..24 FT /evidence="ECO:0007829|PDB:9C91" FT TURN 25..31 FT /evidence="ECO:0007829|PDB:9C91" FT HELIX 32..35 FT /evidence="ECO:0007829|PDB:9C91" FT HELIX 48..54 FT /evidence="ECO:0007829|PDB:9C91" FT STRAND 57..60 FT /evidence="ECO:0007829|PDB:9C91" FT HELIX 66..71 FT /evidence="ECO:0007829|PDB:9C91" FT STRAND 81..83 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 87..89 FT /evidence="ECO:0007829|PDB:6C3M" FT STRAND 90..92 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 93..106 FT /evidence="ECO:0007829|PDB:6C3M" FT STRAND 107..109 FT /evidence="ECO:0007829|PDB:4G38" FT STRAND 112..114 FT /evidence="ECO:0007829|PDB:6C3M" FT STRAND 120..123 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 127..129 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 130..139 FT /evidence="ECO:0007829|PDB:6C3M" FT STRAND 143..145 FT /evidence="ECO:0007829|PDB:4G39" FT TURN 148..150 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 153..155 FT /evidence="ECO:0007829|PDB:4GEP" FT HELIX 164..166 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 167..180 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 187..191 FT /evidence="ECO:0007829|PDB:9C91" FT HELIX 195..198 FT /evidence="ECO:0007829|PDB:9C91" FT TURN 205..207 FT /evidence="ECO:0007829|PDB:2GEP" FT STRAND 218..221 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 230..232 FT /evidence="ECO:0007829|PDB:6C3M" FT STRAND 233..242 FT /evidence="ECO:0007829|PDB:6C3M" FT STRAND 245..253 FT /evidence="ECO:0007829|PDB:6C3M" FT STRAND 272..278 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 279..281 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 282..296 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 302..304 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 307..314 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 316..327 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 333..336 FT /evidence="ECO:0007829|PDB:6C3M" FT STRAND 347..350 FT /evidence="ECO:0007829|PDB:6C3M" FT STRAND 352..354 FT /evidence="ECO:0007829|PDB:4G39" FT STRAND 355..360 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 363..365 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 375..385 FT /evidence="ECO:0007829|PDB:6C3M" FT STRAND 387..392 FT /evidence="ECO:0007829|PDB:6C3M" FT STRAND 398..404 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 405..407 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 408..417 FT /evidence="ECO:0007829|PDB:6C3M" FT TURN 418..421 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 426..429 FT /evidence="ECO:0007829|PDB:6C3M" FT STRAND 431..433 FT /evidence="ECO:0007829|PDB:6C3M" FT TURN 437..439 FT /evidence="ECO:0007829|PDB:6C3M" FT TURN 448..450 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 451..464 FT /evidence="ECO:0007829|PDB:6C3M" FT STRAND 474..479 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 486..488 FT /evidence="ECO:0007829|PDB:6C3M" FT STRAND 489..497 FT /evidence="ECO:0007829|PDB:6C3M" FT STRAND 500..505 FT /evidence="ECO:0007829|PDB:6C3M" FT STRAND 509..511 FT /evidence="ECO:0007829|PDB:4GEP" FT STRAND 516..523 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 524..541 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 548..554 FT /evidence="ECO:0007829|PDB:6C3M" FT HELIX 559..561 FT /evidence="ECO:0007829|PDB:4G38" FT HELIX 564..567 FT /evidence="ECO:0007829|PDB:6C3M" SQ SEQUENCE 570 AA; 63998 MW; 03B41FEE6AB349C6 CRC64; MSEKHPGPLV VEGKLTDAER MKHESNYLRG 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 PARPLKTGLL EIAKIHKGDF RITANQNLII AGVPESEKAK IEKIAKESGL MNAVTPQREN SMACVSFPTC PLAMAEAERF LPSFIDNIDN LMAKHGVSDE HIVMRVTGCP NGCGRAMLAE VGLVGKAPGR YNLHLGGNRI GTRIPRMYKE NITEPEILAS LDELIGRWAK EREAGEGFGD FTVRAGIIRP VLDPARDLWD //