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

CP000462; ABK39442.1; -; Genomic_DNA.

[EMBL / GenBank / DDBJ] [CoDingSequence]

RefSeq

YP_857861.1; -.

3D structure databases

ModBase

A0KNL0.

Ontologies

GO:0004783;	Molecular function: sulfite reductase (NADPH) activity (inferred from electronic annotation from HAMAP).
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

4490553; -.

GenomeReviews

CP000462_GR; AHA_3372.

KEGG

aha:AHA_3372; -.

TIGR

AHA_3372; -.

Other

ProtoNet

A0KNL0.

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_0000292957`
`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: 570 AA [This is the length of the unprocessed precursor]

Molecular weight: 62961 Da [This is the MW of the unprocessed precursor]

CRC64: 3F7378CE7FDFC436 [This is a checksum on the sequence]

        10         20         30         40         50         60 
MSKQLIPGPV EGPLADNERL KRESDHLRGT IAQDLTDPLT GGFNGDNFQL IRFHGMYQQD 

        70         80         90        100        110        120 
DRDIRPERTA QKLEPLHNVM LRARLPGGII TPAQWQVIDK FAEDHSLYGS IRLTTRQTFQ 

       130        140        150        160        170        180 
FHGVLKRDIK MMHQTLNSTG IDSIATAGDV NRNVLCTSNP VESELHQEAY EWAKKISEHL 

       190        200        210        220        230        240 
LPKTRAYVEI WLDGEKLGGD EEPILGSNYL PRKFKTTVVI PPHNDVDIHA NDLNFVAISD 

       250        260        270        280        290        300 
HGKLVGFNVL VGGGLAMTHG DTSTYPRKAS DFGFVPLSHV LEVAAAVVST QRDWGNRVNR 

       310        320        330        340        350        360 
KNAKTKYTLE RVGVEAFKAE VESRAGIQFG PVRPYEFTSR GDRFGWVEGI DGKHHLTLFI 

       370        380        390        400        410        420 
ENGRLLDFPG KPLKTGMLEI AKVHQGDFRL TANQNLIIAG VPAGEKARIE ALARQYGLLD 

       430        440        450        460        470        480 
DGVSEQRKQS MACVALPTCP LAMAEAERML PAFVTDIEGL LAKHELANDA IIFRVTGCPN 

       490        500        510        520        530        540 
GCGRAMLAEV GLVGKAPGRY NLHLGGNLEG TRIPRLHLEN ITEPQILAEL DALIGRWAKD 

       550        560        570 
RNAGECFGDF VIRAGIIAPV IDSARDFYAA

A0KNL0 in FASTA format

View entry in original UniProtKB/Swiss-Prot format
View entry in raw text format (no links)
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	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