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

CP000891; ABX48130.1; -; Genomic_DNA.

[EMBL / GenBank / DDBJ] [CoDingSequence]

RefSeq

YP_001553390.1; -.

3D structure databases

ModBase

A9L2P8.

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.
Graphical view of domain structure.

TIGR02041; CysI; 1.

PS00365; NIR_SIR; 1.

Genome annotation databases

GeneID

5752675; -.

GenomeReviews

CP000891_GR; Sbal195_0954.

KEGG

sbn:Sbal195_0954; -.

CMR

A9L2P8; Sbal195_0954.

Other

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`	`1 565`	`565`	`Sulfite reductase [NADPH] hemoprotein beta-component.`	`PRO_1000087630`
`METAL`	`429 429`		`Iron-sulfur (4Fe-4S) (By similarity).`
`METAL`	`435 435`		`Iron-sulfur (4Fe-4S) (By similarity).`
`METAL`	`474 474`		`Iron-sulfur (4Fe-4S) (By similarity).`
`METAL`	`478 478`		`Iron (siroheme axial ligand) (By similarity).`
`METAL`	`478 478`		`Iron-sulfur (4Fe-4S) (By similarity).`

Sequence information

Length: 565 AA [This is the length of the unprocessed precursor]

Molecular weight: 63022 Da [This is the MW of the unprocessed precursor]

CRC64: 2BA0FF4882AAE71D [This is a checksum on the sequence]

        10         20         30         40         50         60 
MSEQKLALNE YLKTDSDYLR GTIKEGLDSA VTGSFSDGDQ QLIKFHGFYQ QDDRDLRNER 

        70         80         90        100        110        120 
KEQKLEPLYS FMLRARVPGG ICSPQQWLGV DKIASTLTSS NSIRLTTRQT FQYHGIPKRN 

       130        140        150        160        170        180 
LKTIIQDLDR EALDSIAACG DVNRNVMCNP NPVESKLHEQ AYAVAKQLSD HLLPHTRAYA 

       190        200        210        220        230        240 
EIWLDEEKLL STEDETVEPV YGKTYLPRKF KMAVAVPPDN DVDVYTNDLG FIAVAENGEL 

       250        260        270        280        290        300 
VGFNLTAGGG MGSTHGEVET FPRLADDFGF IKTEDVMKFA EAVMTVQRDW GNRVNRKRSR 

       310        320        330        340        350        360 
LKYTIVDHGY EKFKAEVELR AGVKFEPKRD VVIGDRGDRY GWVEGVDGKW HLTLFIESGR 

       370        380        390        400        410        420 
IKDLPGQTLQ TGLREIAKIH KGDFRMTSNQ NMIIAGVAAE DKATIEGLAR KHGLLGQVLT 

       430        440        450        460        470        480 
QTRGHSIACV ALPTCPLAMA EAERYFPEFI DHIDALQAKH GISEQAIVVR MTGCPNGCAR 

       490        500        510        520        530        540 
PFAAEIGLVG KAPGRYNLYL GASFEGTRLN KMHRENIQEA EILAELDTLF GRYAVERDAG 

       550        560 
ETFGNFTVRV GVVKAVIDAA KDFHG

A9L2P8 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