Reviewed, UniProtKB/Swiss-Prot A8ANX0 (CYSI_CITK8)

Names and origin

Protein names

Recommended name:
    Sulfite reductase [NADPH] hemoprotein beta-component
      Short name=SIR-HP
      Short name=SIRHP
    EC=1.8.1.2

Gene names

Name:	cysI
Ordered Locus Names:	CKO_04117

Organism

Citrobacter koseri (strain ATCC BAA-895 / CDC 4225-83 / SGSC4696) [Complete proteome] [HAMAP]

Taxonomic identifier

290338 [NCBI]

Taxonomic lineage

Bacteria › Proteobacteria › Gammaproteobacteria › Enterobacteriales › Enterobacteriaceae › Citrobacter

Protein attributes

Sequence length	570 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is not processed.
Protein existence	Inferred from homology.

General annotation (Comments)

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	H(2)S + 3 NADP(+) + 3 H(2)O = sulfite + 3 NADPH.
Cofactor	Binds 1 siroheme per subunit By similarity. Binds 1 4Fe-4S cluster per subunit By similarity.
Subunit structure	Alpha(8)-beta(4). The alpha component is a flavoprotein, the beta component is a hemoprotein By similarity.
Sequence similarities	Belongs to the nitrite and sulfite reductase 4Fe-4S domain family.

Ontologies

Keywords
Biological process	Amino-acid biosynthesis Cysteine biosynthesis
Ligand	4Fe-4S Heme Iron Iron-sulfur Metal-binding NADP
Molecular function	Oxidoreductase
Technical term	Complete proteome
Gene Ontology (GO)
Biological process	cysteine biosynthetic process Inferred from electronic annotation. Source: UniProtKB-KW oxidation reduction Inferred from electronic annotation. Source: UniProtKB-KW sulfate assimilation Inferred from electronic annotation. Source: HAMAP
Cellular component	sulfite reductase complex (NADPH) Inferred from electronic annotation. Source: InterPro
Molecular function	4 iron, 4 sulfur cluster binding Inferred from electronic annotation. Source: InterPro NADP binding Inferred from electronic annotation. Source: InterPro electron carrier activity Inferred from electronic annotation. Source: InterPro heme binding Inferred from electronic annotation. Source: InterPro iron ion binding Inferred from electronic annotation. Source: UniProtKB-KW sulfite reductase (NADPH) activity Inferred from electronic annotation. Source: HAMAP
Complete GO annotation...

Sequence annotation (Features)

	Feature key	Position(s)	Length	Description	Graphical view	Feature identifier
Molecule processing
	Chain	1 – 570	570	Sulfite reductase [NADPH] hemoprotein beta-component		PRO_1000068757
Sites
	Metal binding	434	1	Iron-sulfur (4Fe-4S) By similarity
	Metal binding	440	1	Iron-sulfur (4Fe-4S) By similarity
	Metal binding	479	1	Iron-sulfur (4Fe-4S) By similarity
	Metal binding	483	1	Iron (siroheme axial ligand) By similarity
	Metal binding	483	1	Iron-sulfur (4Fe-4S) By similarity

Sequences

	Sequence		Length	Mass (Da)
	A8ANX0-1 [UniParc]. Last modified October 23, 2007. Version 1. Checksum: 63346FE6C3BEDDE8	FASTA	570	64,076
	10 20 30 40 50 60 MSEKHPGPLV VEGKLADAER MKLESNYLRG TIAEDLNDGL TGGFKGDNFL LIRFHGMYQQ 70 80 90 100 110 120 DDRDIRAERA EQKLEPRHAM LLRCRLPGGV ITTRQWQAID KFAAENTIYG SIRLTNRQTF 130 140 150 160 170 180 QFHGILKKNV KPVHQMLHSV GLDALATAND MNRNVLCTSN PYESELHAEA YEWAKKISEH 190 200 210 220 230 240 LLPRTRAYAE IWLDQEKVAT TDEEPILGQT YLPRKFKTTV VIPPQNDIDL HANDMNFVAV 250 260 270 280 290 300 AENGKLVGFN LLVGGGLSIE HGNKKTYART ASEFGYLPLE HTLAVAEAVV TTQRDWGNRT 310 320 330 340 350 360 DRKNAKTKYT LERVGVETFK AEVERRAGIK FEPIRPYEFT GRGDRIGWVK GIDNKWHLTL 370 380 390 400 410 420 FIENGRILDY PGRPLKTGLL EIAKIHKGEF RITANQNLII AGVPESQKAK IEKLARNHGL 430 440 450 460 470 480 MNAVTSQREN SMACVSFPTC PLAMAEAERF LPTFVDKVDA LMTHHGVSDE HIVLRVTGCP 490 500 510 520 530 540 NGCGRAMLAE VGLVGKAPGR YNLHLGGNRI GTRIPRMFKE NITEPEILAS LDELIGRWVK 550 560 570 EREAGEGFGD FTVRAGIIRP VLDPARDFWE

References

[1]	McClelland M., Sanderson E.K., Porwollik S., Spieth J., Clifton W.S., Latreille P., Courtney L., Wang C., Pepin K., Bhonagiri V., Nash W., Johnson M., Thiruvilangam P., Wilson R. Submitted (AUG-2007) to the EMBL/GenBank/DDBJ databases Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].

Cross-references

Sequence databases
EMBLGenBankDDBJ	CP000822 Genomic DNA. Translation: ABV15183.1.
RefSeq	YP_001455619.1.
3D structure databases
ModBase	Search...
Genome annotation databases
GeneID	5584355.
GenomeReviews	Gene locus CKO_04117 in contig CP000822_GR.
KEGG	cko:CKO_04117.
Organism-specific databases
CMR	Search...
Family and domain databases
HAMAP	MF_01540. [Tree]
InterPro	IPR011786. CysI. IPR006066. Nir_Si_BS. IPR006067. Nir_Sir_4Fe4S. IPR005117. NiRdtase/SiRdtase_haem-b_fer. [Graphical view]
Pfam	PF01077. NIR_SIR. 1 hit. PF03460. NIR_SIR_ferr. 2 hits. [Graphical view]
PRINTS	PR00397. SIROHAEM.
TIGRFAMs	TIGR02041. CysI. 1 hit.
PROSITE	PS00365. NIR_SIR. 1 hit. [Graphical view]
ProtoNet	Search...

Entry information

Entry name

CYSI_CITK8

Accession

Primary (citable) accession number: A8ANX0

Entry history

Integrated into UniProtKB/Swiss-Prot:	February 5, 2008
Last sequence update:	October 23, 2007
Last modified:	November 25, 2008
This is version 10 of the entry and version 1 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation project

HAMAP (High-quality Automated and Manual Annotation of microbial Proteomes)