AC   MF_00331;
DC   Protein; auto
TR   HAMAP; MF_00331; -; 1; level=0
XX
Names: Cys_desulf_IscS
XX
ID   ISCS
DE   RecName: Full=Cysteine desulfurase IscS;
DE            EC=2.8.1.7;
GN   Name=iscS;
XX
case <OC:Escherichia> or <OC:Shigella> or <OC:Salmonella>
CC   -!- FUNCTION: Master enzyme that delivers sulfur to a number of partners
CC       involved in Fe-S cluster assembly, tRNA modification or cofactor
CC       biosynthesis. Catalyzes the removal of elemental sulfur and selenium
CC       atoms from cysteine and selenocysteine to produce alanine. Functions as
CC       a sulfur delivery protein for Fe-S cluster synthesis onto IscU, an Fe-S
CC       scaffold assembly protein, as well as other S acceptor proteins. Also
CC       functions as a selenium delivery protein in the pathway for the
CC       biosynthesis of selenophosphate.
else
CC   -!- FUNCTION: Master enzyme that delivers sulfur to a number of partners
CC       involved in Fe-S cluster assembly, tRNA modification or cofactor
CC       biosynthesis. Catalyzes the removal of elemental sulfur atoms from
CC       cysteine to produce alanine. Functions as a sulfur delivery protein for
CC       Fe-S cluster synthesis onto IscU, an Fe-S scaffold assembly protein, as
CC       well as other S acceptor proteins.
end case
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=[sulfur carrier]-H + L-cysteine = [sulfur carrier]-SH + L-
CC         alanine; Xref=Rhea:RHEA:43892, Rhea:RHEA-COMP:14737, Rhea:RHEA-
CC         COMP:14739, ChEBI:CHEBI:29917, ChEBI:CHEBI:35235, ChEBI:CHEBI:57972,
CC         ChEBI:CHEBI:64428; EC=2.8.1.7;
CC   -!- COFACTOR:
CC       Name=pyridoxal 5'-phosphate; Xref=ChEBI:CHEBI:597326;
CC   -!- PATHWAY: Cofactor biosynthesis; iron-sulfur cluster biosynthesis.
CC   -!- SUBUNIT: Homodimer. Forms a heterotetramer with IscU, interacts with
CC       other sulfur acceptors.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm.
case <OC:Archaea>
CC   -!- MISCELLANEOUS: In Archaea the pyridoxal phosphate cofactor is not
CC       covalently bound to Lys but ligated by other amino acids.
end case
CC   -!- SIMILARITY: Belongs to the class-V pyridoxal-phosphate-dependent
CC       aminotransferase family. NifS/IscS subfamily.
XX
DR   Pfam; PF00266; Aminotran_5; 1; trigger=no
DR   PIRSF; PIRSF005572; NifS; 1; trigger=no
DR   NCBIfam; TIGR02006; IscS; 1; trigger=no
DR   NCBIfam; TIGR03402; FeS_nifS; 1; trigger=no
DR   NCBIfam; TIGR03403; nifS_epsilon; 1; trigger=no
DR   PROSITE; PS00595; AA_TRANSFER_CLASS_5; 1; trigger=no
XX
KW   Cytoplasm
KW   Transferase
KW   Pyridoxal phosphate
case <FTTag:IronSulfur>
KW   2Fe-2S
KW   Iron
KW   Iron-sulfur
KW   Metal-binding
end case
XX
GO   GO:0005737; C:cytoplasm
GO   GO:0030170; F:pyridoxal phosphate binding
GO   GO:0031071; F:cysteine desulfurase activity
case <FTTag:IronSulfur>
GO   GO:0051537; F:2 iron, 2 sulfur cluster binding
end case
GO   GO:0044571; P:[2Fe-2S] cluster assembly
XX
FT   From: ISCS_ECO57 (P0A6B9)
FT   BINDING         75..76
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT   Condition: [AG]-[TS]
FT   BINDING         203..205
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT   Condition: [TS]-x-H
FT   ACT_SITE        328
FT                   /note="Cysteine persulfide intermediate"
FT   Condition: C
FT   BINDING         328
FT                   /ligand="[2Fe-2S] cluster"
FT                   /ligand_id="ChEBI:CHEBI:190135"
FT                   /ligand_note="ligand shared with IscU"
FT                   /note="via persulfide group"
FT   Tag: IronSulfur; Condition: C
FT   BINDING         155
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT   Condition: N
FT   BINDING         183
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT   Condition: Q
FT   BINDING         243
FT                   /ligand="pyridoxal 5'-phosphate"
FT                   /ligand_id="ChEBI:CHEBI:597326"
FT   Condition: [TS]
case <OC:Bacteria>
FT   MOD_RES         206
FT                   /note="N6-(pyridoxal phosphate)lysine"
FT   Condition: K
end case
XX
Size: 375-410;
Related: None;
Template: P0A6B7; O31269; O29689; P0A6B9;
Scope:
 Bacteria
 Archaea
Fusion:
 Nter: None
 Cter: None
Duplicate: in ARCFU
Plasmid: None
Comments: Divergent HALH5 and BACSU; sequences not included in alignment
XX
# Revision 1.43 2023/06/01
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