AC   MF_01540;
DC   Protein; auto
TR   HAMAP; MF_01540; -; 1; level=0
XX
Names: CysI
XX
ID   CYSI
DE   RecName: Full=Sulfite reductase [NADPH] hemoprotein beta-component;
DE            Short=SiR-HP;
DE            Short=SiRHP;
DE            EC=1.8.1.2;
GN   Name=cysI;
XX
CC   -!- FUNCTION: Component of the sulfite reductase complex that catalyzes the
CC       6-electron reduction of sulfite to sulfide. This is one of several
CC       activities required for the biosynthesis of L-cysteine from sulfate.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=3 H2O + hydrogen sulfide + 3 NADP(+) = 4 H(+) + 3 NADPH +
CC         sulfite; Xref=Rhea:RHEA:13801, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378,
CC         ChEBI:CHEBI:17359, ChEBI:CHEBI:29919, ChEBI:CHEBI:57783,
CC         ChEBI:CHEBI:58349; EC=1.8.1.2;
CC   -!- COFACTOR:
CC       Name=siroheme; Xref=ChEBI:CHEBI:60052;
CC       Note=Binds 1 siroheme per subunit.;
CC   -!- COFACTOR:
CC       Name=[4Fe-4S] cluster; Xref=ChEBI:CHEBI:49883;
CC       Note=Binds 1 [4Fe-4S] cluster per subunit.;
CC   -!- PATHWAY: Sulfur metabolism; hydrogen sulfide biosynthesis; hydrogen
CC       sulfide from sulfite (NADPH route): step 1/1.
CC   -!- SUBUNIT: Alpha(8)-beta(8). The alpha component is a flavoprotein, the
CC       beta component is a hemoprotein.
CC   -!- SIMILARITY: Belongs to the nitrite and sulfite reductase 4Fe-4S domain
CC       family.
XX
DR   PROSITE; PS00365; NIR_SIR; 1; trigger=no
DR   Pfam; PF01077; NIR_SIR; 1; trigger=no
DR   Pfam; PF03460; NIR_SIR_ferr; 2; trigger=no
DR   PRINTS; PR00397; SIROHAEM; 1; trigger=no
DR   NCBIfam; TIGR02041; CysI; 1; trigger=no
XX
KW   4Fe-4S
KW   Amino-acid biosynthesis
KW   Cysteine biosynthesis
KW   Heme
KW   Iron
KW   Iron-sulfur
KW   Metal-binding
KW   NADP
KW   Oxidoreductase
XX
GO   GO:0004783; F:sulfite reductase (NADPH) activity
GO   GO:0000103; P:sulfate assimilation
GO   GO:0070814; P:hydrogen sulfide biosynthetic process
XX
FT   From: CYSI_ECOLI (P17846)
FT   BINDING         434
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT   Condition: C
FT   BINDING         440
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT   Condition: C
FT   BINDING         479
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT   Condition: C
FT   BINDING         483
FT                   /ligand="siroheme"
FT                   /ligand_id="ChEBI:CHEBI:60052"
FT                   /ligand_part="Fe"
FT                   /ligand_part_id="ChEBI:CHEBI:18248"
FT                   /note="axial binding residue"
FT   Condition: C
FT   BINDING         483
FT                   /ligand="[4Fe-4S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:49883"
FT   Condition: C
XX
Size: 555-616;
Related: None;
Template: P17846; P17845; O32213; Q8KQT8;
Scope:
 Bacteria
Fusion:
 Nter: None
 Cter: None
Duplicate: in KLEP3, NEIMB, PECCP
Plasmid: None
Comments: None
XX
# Revision 1.16 2023/06/01
//