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

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Cross-references

Sequence databases

EMBL

CP000388; ABG42537.1; -; Genomic_DNA.

[EMBL / GenBank / DDBJ] [CoDingSequence]

RefSeq

YP_663591.1; -.

3D structure databases

ModBase

Q15NK1.

Enzyme and pathway databases

BioCyc

PATL342610:PATL_4038-MON; -.

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.

PR00397; SIROHAEM.

TIGR02041; CysI; 1.

PS00365; NIR_SIR; 1.

Genome annotation databases

GeneID

4175827; -.

GenomeReviews

CP000388_GR; Patl_4038.

KEGG

pat:Patl_4038; -.

NMPDR

fig|342610.3.peg.2295; -.

Phylogenomic databases

HOGENOM

Q15NK1; -.

Genome annotation databases

CMR

Q15NK1; Patl_4038.

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`	`1 569`	`569`	`Sulfite reductase [NADPH] hemoprotein beta-component.`	`PRO_0000292961`
`METAL`	`433 433`		`Iron-sulfur (4Fe-4S) (By similarity).`
`METAL`	`439 439`		`Iron-sulfur (4Fe-4S) (By similarity).`
`METAL`	`478 478`		`Iron-sulfur (4Fe-4S) (By similarity).`
`METAL`	`482 482`		`Iron (siroheme axial ligand) (By similarity).`
`METAL`	`482 482`		`Iron-sulfur (4Fe-4S) (By similarity).`

Sequence information

Length: 569 AA [This is the length of the unprocessed precursor]

Molecular weight: 63144 Da [This is the MW of the unprocessed precursor]

CRC64: 46A2EFB0690E54C4 [This is a checksum on the sequence]

        10         20         30         40         50         60 
MTTDNKFVVE GKLADNERLK GESNFLRGTI AEDLKDDLTG AFVGDNFQLI RFHGMYQQDD 

        70         80         90        100        110        120 
RDLRAERAKQ KLEPLQNVML RARLPGGIIK PQQWLAIDKF AEEKSLYGSI RLTTRQTFQF 

       130        140        150        160        170        180 
HGVLKPNIKL MHQTLNQVGI DSIATAGDVN RNVLCTSNPI ESAVHQEAYE WATKISEHLL 

       190        200        210        220        230        240 
PKTRAYAEIW LDGEKKETTD HEPILGANYL PRKFKTTVAI PPLNDVDVHA NDLNFIAISK 

       250        260        270        280        290        300 
DGKLVGFNVL VGGGLAMTHG DHATFPRKAS DFGFIKVEDT LAIAEAVVST QRDWGNRVNR 

       310        320        330        340        350        360 
KNAKTKYTLE RVGVENFKAE VEKRSGVTFG ESQAYEFTER GDRIGWVEGI DGKHHLTLFI 

       370        380        390        400        410        420 
ENGRILDYPG KPLKTGCAEI AKIHDGDFRL TANQNLIVAG VSEQNKAKVE EIARAHGLIE 

       430        440        450        460        470        480 
DDLSAQRKDS MACVALPTCP LAMAEAERYL PEAVTQLEGI LAKHAIAQKS IIYRVTGCPN 

       490        500        510        520        530        540 
GCGRSMLAEI GLVGKGPGKY NLHLGGNRQG TRIPKMYKEN IGEQQIMDEL DVLIGQWAKE 

       550        560 
AQSDESFGDF VIRTGVIAEV VNSAEDFYA

Q15NK1 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