AC   MF_00421;
DC   Protein; auto
TR   HAMAP; MF_00421; -; 1; level=0
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Names: PurQ
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ID   PURQ
DE   RecName: Full=Phosphoribosylformylglycinamidine synthase subunit PurQ;
DE            Short=FGAM synthase;
DE            EC=6.3.5.3;
DE   AltName: Full=Formylglycinamide ribonucleotide amidotransferase subunit I;
DE            Short=FGAR amidotransferase I;
DE            Short=FGAR-AT I;
DE   AltName: Full=Phosphoribosylformylglycinamidine synthase subunit I;
DE   AltName: Full=Glutaminase PurQ;
DE            EC=3.5.1.2;
GN   Name=purQ;
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CC   -!- FUNCTION: Part of the phosphoribosylformylglycinamidine synthase
CC       complex involved in the purines biosynthetic pathway. Catalyzes the
CC       ATP-dependent conversion of formylglycinamide ribonucleotide (FGAR) and
CC       glutamine to yield formylglycinamidine ribonucleotide (FGAM) and
CC       glutamate. The FGAM synthase complex is composed of three subunits.
CC       PurQ produces an ammonia molecule by converting glutamine to glutamate.
CC       PurL transfers the ammonia molecule to FGAR to form FGAM in an ATP-
CC       dependent manner. PurS interacts with PurQ and PurL and is thought to
CC       assist in the transfer of the ammonia molecule from PurQ to PurL.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=ATP + H2O + L-glutamine + N(2)-formyl-N(1)-(5-phospho-beta-D-
CC         ribosyl)glycinamide = 2-formamido-N(1)-(5-O-phospho-beta-D-
CC         ribosyl)acetamidine + ADP + H(+) + L-glutamate + phosphate;
CC         Xref=Rhea:RHEA:17129, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378,
CC         ChEBI:CHEBI:29985, ChEBI:CHEBI:30616, ChEBI:CHEBI:43474,
CC         ChEBI:CHEBI:58359, ChEBI:CHEBI:147286, ChEBI:CHEBI:147287,
CC         ChEBI:CHEBI:456216; EC=6.3.5.3;
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=H2O + L-glutamine = L-glutamate + NH4(+);
CC         Xref=Rhea:RHEA:15889, ChEBI:CHEBI:15377, ChEBI:CHEBI:28938,
CC         ChEBI:CHEBI:29985, ChEBI:CHEBI:58359; EC=3.5.1.2;
CC   -!- PATHWAY: Purine metabolism; IMP biosynthesis via de novo pathway; 5-
CC       amino-1-(5-phospho-D-ribosyl)imidazole from N(2)-formyl-N(1)-(5-
CC       phospho-D-ribosyl)glycinamide: step 1/2.
CC   -!- SUBUNIT: Part of the FGAM synthase complex composed of 1 PurL, 1 PurQ
CC       and 2 PurS subunits.
CC   -!- SUBCELLULAR LOCATION: Cytoplasm.
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DR   PROSITE; PS51273; GATASE_TYPE_1; 1; trigger=yes
DR   NCBIfam; TIGR01737; FGAM_synth_I; 1; trigger=no
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KW   ATP-binding
KW   Cytoplasm
KW   Glutamine amidotransferase
KW   Hydrolase
KW   Ligase
KW   Nucleotide-binding
KW   Purine biosynthesis
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GO   GO:0004642; F:phosphoribosylformylglycinamidine synthase activity
GO   GO:0006189; P:'de novo' IMP biosynthetic process
GO   GO:0005737; C:cytoplasm
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FT   From: PURQ_THEMA (Q9X0X2)
FT   ACT_SITE        86
FT                   /note="Nucleophile"
FT   Condition: C
FT   ACT_SITE        186
FT   Condition: H
FT   ACT_SITE        188
FT   Condition: E
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Size: 212-272;
Related: MF_00419;
Template: P12041; Q9X0X2;
Scope:
 Bacteria
 Archaea
Fusion:
 Nter: None
 Cter: None
Duplicate: None
Plasmid: None
Comments: FGAM synthase can be composed of a single polypeptide (large PurL, MF_00419),
 or it can be composed of three separate proteins: PurL (small PurL, MF_00420), PurQ (MF_00421)
 and PurS (MF_01926).
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# Revision 1.44 2023/06/01
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