AC   MF_03221;
DC   Protein; auto
c?   <OC:Metazoa> or <OC:Amoebozoa>
TR   HAMAP; MF_03221; -; 1; level=0
XX
Names: Succ_CoA_betaG_euk
XX
ID   SUCB2
DE   RecName: Full=Succinate--CoA ligase [GDP-forming] subunit beta, mitochondrial;
DE            EC=6.2.1.4;
DE   AltName: Full=GTP-specific succinyl-CoA synthetase subunit beta;
DE            Short=G-SCS;
DE            Short=GTPSCS;
DE   AltName: Full=Succinyl-CoA synthetase beta-G chain;
DE            Short=SCS-betaG;
case <OC:Vertebrata>
GN   Name=SUCLG2;
end case
XX
CC   -!- FUNCTION: GTP-specific succinyl-CoA synthetase functions in the citric
CC       acid cycle (TCA), coupling the hydrolysis of succinyl-CoA to the
CC       synthesis of GTP and thus represents the only step of substrate-level
CC       phosphorylation in the TCA. The beta subunit provides nucleotide
CC       specificity of the enzyme and binds the substrate succinate, while the
CC       binding sites for coenzyme A and phosphate are found in the alpha
CC       subunit.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=CoA + GTP + succinate = GDP + phosphate + succinyl-CoA;
CC         Xref=Rhea:RHEA:22120, ChEBI:CHEBI:30031, ChEBI:CHEBI:37565,
CC         ChEBI:CHEBI:43474, ChEBI:CHEBI:57287, ChEBI:CHEBI:57292,
CC         ChEBI:CHEBI:58189; EC=6.2.1.4;
case <FTGroup:1>
CC   -!- COFACTOR:
CC       Name=Mg(2+); Xref=ChEBI:CHEBI:18420;
CC       Note=Binds 1 Mg(2+) ion per subunit.;
end case
CC   -!- PATHWAY: Carbohydrate metabolism; tricarboxylic acid cycle; succinate
CC       from succinyl-CoA (ligase route): step 1/1.
CC   -!- SUBUNIT: Heterodimer of an alpha and a beta subunit. The beta subunit
CC       determines specificity for GTP.
CC   -!- SUBCELLULAR LOCATION: Mitochondrion.
CC   -!- SIMILARITY: Belongs to the succinate/malate CoA ligase beta subunit
CC       family. GTP-specific subunit beta subfamily.
case not <AnyFeature:TransitM>
CC   -!- MISCELLANEOUS: This protein may be expected to contain an N-terminal
CC       transit peptide but none has been predicted.
end case
XX
DR   PROSITE; PS01217; SUCCINYL_COA_LIG_3; 1; trigger=no
DR   PROSITE; PS50975; ATP_GRASP; 1; trigger=no
DR   Pfam; PF08442; ATP-grasp_2; 1; trigger=no
DR   Pfam; PF00549; Ligase_CoA; 1; trigger=no
DR   NCBIfam; TIGR01016; sucCoAbeta; 1; trigger=no
DR   PIRSF; PIRSF001554; SucCS_beta; 1; trigger=no
DR   General; TransitM; -; 0-1; trigger=yes
XX
KW   GTP-binding
KW   Ligase
case <FTGroup:1>
KW   Magnesium
KW   Metal-binding
end case
KW   Mitochondrion
KW   Nucleotide-binding
KW   Tricarboxylic acid cycle
XX
GO   GO:0005525; F:GTP binding
case <FTGroup:1>
GO   GO:0000287; F:magnesium ion binding
end case
GO   GO:0004775; F:succinate-CoA ligase (ADP-forming) activity
GO   GO:0006099; P:tricarboxylic acid cycle
XX
FT   From: SUCB2_PIG (P53590)
case <Feature:PS50975>
FT   DOMAIN          47..275
FT                   /note="ATP-grasp"
end case
FT   BINDING         91..93
FT                   /ligand="GTP"
FT                   /ligand_id="ChEBI:CHEBI:37565"
FT   Condition: G-R-G
FT   BINDING         366..368
FT                   /ligand="substrate"
FT                   /ligand_note="ligand shared with subunit alpha"
FT   Condition: G-I-[VM]
FT   BINDING         244
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT   Group: 1; Condition: N
FT   BINDING         258
FT                   /ligand="Mg(2+)"
FT                   /ligand_id="ChEBI:CHEBI:18420"
FT   Group: 1; Condition: D
FT   BINDING         58
FT                   /ligand="GTP"
FT                   /ligand_id="ChEBI:CHEBI:37565"
FT   Condition: Q
FT   BINDING         147
FT                   /ligand="GTP"
FT                   /ligand_id="ChEBI:CHEBI:37565"
FT   BINDING         309
FT                   /ligand="substrate"
FT                   /ligand_note="ligand shared with subunit alpha"
FT   Condition: N
FT   SITE            80
FT                   /note="Important for substrate specificity"
FT   Condition: E
FT   SITE            148
FT                   /note="Important for substrate specificity"
FT   Condition: [DN]
XX
Size: 367-542;
Related: MF_00558; MF_03220;
Template: P53590;
Scope:
 Eukaryota
Fusion:
 Nter: None
 Cter: None
Duplicate: in CANLF
Plasmid: None
Comments: In animals, two different isoforms of SCS exist, one specific for ATP and the
 other specific for GTP (PubMed:9765291). The two isoforms include the same alpha-subunit,
 but different beta-subunits (PubMed:9765290). This is the subfamily of GTP-specific
 beta subunits.
XX
# Revision 1.9 2023/06/01
//