FUNCTION: This enzyme catalyzes the 6-electron reduction of sulfite to sulfide. This is one of several activities required for the biosynthesis of L-cysteine from sulfate (By similarity).
CATALYTIC ACTIVITY: H₂S + 3 NADP⁺ + 3 H₂O = sulfite + 3 NADPH.
COFACTOR: Binds 1 siroheme per subunit (By similarity).
COFACTOR: Binds 1 4Fe-4S cluster per subunit (By similarity).
SUBUNIT: Alpha(8)-beta(4). The alpha component is a flavoprotein, the beta component is a hemoprotein (By similarity).
SIMILARITY: Belongs to the nitrite and sulfite reductase 4Fe-4S domain family.

Copyright

Copyrighted by the UniProt Consortium, see http://www.uniprot.org/terms. Distributed under the Creative Commons Attribution-NoDerivs License.

Cross-references

Sequence databases

EMBL

CP000946; ACA76618.1; -; Genomic_DNA.

[EMBL / GenBank / DDBJ] [CoDingSequence]

RefSeq

YP_001723945.1; -.

3D structure databases

ModBase

B1IU78.

Ontologies

GO:0009337;	Cellular component: sulfite reductase complex (NADPH) (inferred from electronic annotation from InterPro).
GO:0051539;	Molecular function: 4 iron, 4 sulfur cluster binding (inferred from electronic annotation from InterPro).
GO:0009055;	Molecular function: electron carrier activity (inferred from electronic annotation from InterPro).
GO:0020037;	Molecular function: heme binding (inferred from electronic annotation from InterPro).
GO:0005506;	Molecular function: iron ion binding (inferred from electronic annotation from UniProtKB-KW).
GO:0050661;	Molecular function: NADP binding (inferred from electronic annotation from InterPro).
GO:0004783;	Molecular function: sulfite reductase (NADPH) activity (inferred from electronic annotation from HAMAP).
GO:0019344;	Biological process: cysteine biosynthetic process (inferred from electronic annotation from UniProtKB-KW).
GO:0055114;	Biological process: oxidation reduction (inferred from electronic annotation from UniProtKB-KW).
GO:0000103;	Biological process: sulfate assimilation (inferred from electronic annotation from HAMAP).
QuickGo view.

Family and domain databases

HAMAP

MF_01540; -; 1.
PBIL [Tree]

InterPro

IPR011786; CysI.
IPR006066; Nir_Si_BS.
IPR006067; Nir_Sir_4Fe4S.
IPR005117; NiRdtase/SiRdtase_haem-b_fer.
Graphical view of domain structure.

Pfam

PF01077; NIR_SIR; 1.
PF03460; NIR_SIR_ferr; 2.
Pfam graphical view of domain structure.

PROSITE

PS00365; NIR_SIR; 1.

Genome annotation databases

GeneID

6068350; -.

GenomeReviews

CP000946_GR; EcolC_0949.

KEGG

ecl:EcolC_0949; -.

CMR

B1IU78; EcolC_0949.

Other

ProtoNet

B1IU78.

UniRef

View cluster of proteins with at least 50% / 90% / 100% identity.

Keywords

4Fe-4S; Amino-acid biosynthesis; Complete proteome; Cysteine biosynthesis; Heme; Iron; Iron-sulfur; Metal-binding; NADP; Oxidoreductase.

Features

Feature table viewer

`Key`	`From To`	`Length`	`Description`	`FTId`
`CHAIN`	`1 570`	`570`	`Sulfite reductase [NADPH] hemoprotein beta-component.`	`PRO_1000087626`
`METAL`	`434 434`		`Iron-sulfur (4Fe-4S) (By similarity).`
`METAL`	`440 440`		`Iron-sulfur (4Fe-4S) (By similarity).`
`METAL`	`479 479`		`Iron-sulfur (4Fe-4S) (By similarity).`
`METAL`	`483 483`		`Iron (siroheme axial ligand) (By similarity).`
`METAL`	`483 483`		`Iron-sulfur (4Fe-4S) (By similarity).`

Sequence information

Length: 570 AA [This is the length of the unprocessed precursor]

Molecular weight: 63990 Da [This is the MW of the unprocessed precursor]

CRC64: 4728279022CA433F [This is a checksum on the sequence]

        10         20         30         40         50         60 
MSEKHPGPLV VEGKLTDAER MKLESNYLRG TIAEDLNDGL TGGFKGDNFL LIRFHGMYQQ 

        70         80         90        100        110        120 
DDRDIRAERA EQKLEPRHAM LLRCRLPGGV ITTKQWQAID KFAGENTIYG SIRLTNRQTF 

       130        140        150        160        170        180 
QFHGILKKNV KPVHQMLHSV GLDALATAND MNRNVLCTSN PYESQLHAEA YEWAKKISEH 

       190        200        210        220        230        240 
LLPRTRAYAE IWLDQEKVAT TDEEPILGQT YLPRKFKTTV VIPPQNDIDL HANDMNFVAI 

       250        260        270        280        290        300 
AENGKLVGFN LLVGGGLSIE HGNKKTYART ASEFGYLPLE HTLAVAEAVV TTQRDWGNRT 

       310        320        330        340        350        360 
DRKNAKTKYT LERVGVETFK AEVERRAGIK FEPIRPYEFT GRGDRIGWVK GIDDNWHLTL 

       370        380        390        400        410        420 
FIENGRILDY PGRPLKTGLL EIAKIHKGDF RITANQNLII AGVPESEKAK IEKIAKESGL 

       430        440        450        460        470        480 
MNAVTPQREN SMACVSFPTC PLAMAEAERF LPSFIDNIDN LMAKHGVSDE HIVMRVTGCP 

       490        500        510        520        530        540 
NGCGRAMLAE VGLVGKAPGR YNLHLSGNRI GTRIPRMYKE NITEPEILAS LDELIGRWAK 

       550        560        570 
EREAGEGFGD FTVRAGIIRP VLDPARDLWD

B1IU78 in FASTA format

View entry in original UniProtKB/Swiss-Prot format
View entry in raw text format (no links)
Report form for errors/updates in this UniProtKB/Swiss-Prot entry

	BLAST submission on ExPASy/SIB or at NCBI (USA)		Sequence analysis tools: ProtParam, ProtScale, Compute pI/Mw, PeptideMass, PeptideCutter, Dotlet (Java)
	ScanProsite, MotifScan		Submit a homology modeling request to SWISS-MODEL
	NPSA Sequence analysis tools