HAMAP rule MF_00121

General rule information [?]

PURL	https://purl.expasy.org/hamap/rule/MF_00121
Accession	MF_00121
Dates	28-FEB-2005 (Created) 22-MAY-2026 (Last updated, Version )
Name	GatB
Scope(s)	Bacteria Archaea
Template(s)	O30509 (GATB_BACSU); Q9LCX2 (GATB_THET8); O27341 (GATB_METTH); P64201 (GATB_STAAM); [ Recover all ]
Triggered by	case c? <OC:Bacteria> or <OC:Archaea> HAMAP; MF_00121 (Get profile general information and statistics) end case

Propagated annotation [?]

Identifier, protein and gene names [?]

Identifier	GATB
Protein name	RecName: Full=Aspartyl/glutamyl-tRNA(Asn/Gln) amidotransferase subunit B; Short=Asp/Glu-ADT subunit B; EC=6.3.5.6; EC=6.3.5.7; AltName: Full=Glutamyl-tRNA(Gln) amidotransferase subunit B; Short=Glu-ADT subunit B;
Gene name	Name=gatB;

Comments [?]

FUNCTION	Catalytic subunit of the Asp/Glu-tRNA(Asn/Gln) amidotransferase complex GatCAB. GatCAB allows the formation of correctly charged Asn-tRNA(Asn) or Gln-tRNA(Gln) through the multi-step transamidation of misacylated Asp-tRNA(Asn) or Glu-tRNA(Gln) in organisms which lack either or both of asparaginyl-tRNA or glutaminyl- tRNA synthetases. The reaction takes place in the presence of glutamine and ATP through an activated phospho-Asp-tRNA(Asn) or phospho-Glu- tRNA(Gln). This subunit specifically recognizes tRNA(Gln) and tRNA(Asn), and mediates the transamidation of misloaded Glu and Asp respectively by catalyzing formation of the activated gamma-phospho- intermediate and its subsequent aminolysis using ammonia produced by the gatA subunit. Recognizes the first base pair and the D-loop of its specific tRNA substrates.
CATALYTIC ACTIVITY	Reaction=L-glutamyl-tRNA(Gln) + L-glutamine + ATP + H2O = L-glutaminyl- tRNA(Gln) + L-glutamate + ADP + phosphate + H(+); Xref=Rhea:RHEA:17521, Rhea:RHEA-COMP:9681, Rhea:RHEA-COMP:9684, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:29985, ChEBI:CHEBI:30616, ChEBI:CHEBI:43474, ChEBI:CHEBI:58359, ChEBI:CHEBI:78520, ChEBI:CHEBI:78521, ChEBI:CHEBI:456216; EC=6.3.5.7;
CATALYTIC ACTIVITY	Reaction=L-aspartyl-tRNA(Asn) + L-glutamine + ATP + H2O = L- asparaginyl-tRNA(Asn) + L-glutamate + ADP + phosphate + 2 H(+); Xref=Rhea:RHEA:14513, Rhea:RHEA-COMP:9674, Rhea:RHEA-COMP:9677, ChEBI:CHEBI:15377, ChEBI:CHEBI:15378, ChEBI:CHEBI:29985, ChEBI:CHEBI:30616, ChEBI:CHEBI:43474, ChEBI:CHEBI:58359, ChEBI:CHEBI:78515, ChEBI:CHEBI:78516, ChEBI:CHEBI:456216; EC=6.3.5.6;
CATALYTIC ACTIVITY	Reaction=L-glutamyl-tRNA(Gln) + ATP = 5-phospho-L-glutamyl-tRNA(Gln) + ADP; Xref=Rhea:RHEA:57908, Rhea:RHEA-COMP:9684, Rhea:RHEA-COMP:15032, ChEBI:CHEBI:30616, ChEBI:CHEBI:78520, ChEBI:CHEBI:142449, ChEBI:CHEBI:456216;
CATALYTIC ACTIVITY	Reaction=L-aspartyl-tRNA(Asn) + ATP = 4-phospho-L-aspartyl-tRNA(Asn) + ADP + H(+); Xref=Rhea:RHEA:57916, Rhea:RHEA-COMP:9677, Rhea:RHEA- COMP:15033, ChEBI:CHEBI:15378, ChEBI:CHEBI:30616, ChEBI:CHEBI:78516, ChEBI:CHEBI:142450, ChEBI:CHEBI:456216;
CATALYTIC ACTIVITY	Reaction=5-phospho-L-glutamyl-tRNA(Gln) + NH4(+) = L-glutaminyl- tRNA(Gln) + phosphate + H(+); Xref=Rhea:RHEA:57912, Rhea:RHEA- COMP:9681, Rhea:RHEA-COMP:15032, ChEBI:CHEBI:15378, ChEBI:CHEBI:28938, ChEBI:CHEBI:43474, ChEBI:CHEBI:78521, ChEBI:CHEBI:142449;
CATALYTIC ACTIVITY	Reaction=4-phospho-L-aspartyl-tRNA(Asn) + NH4(+) = L-asparaginyl- tRNA(Asn) + phosphate + H(+); Xref=Rhea:RHEA:57920, Rhea:RHEA- COMP:9674, Rhea:RHEA-COMP:15033, ChEBI:CHEBI:15378, ChEBI:CHEBI:28938, ChEBI:CHEBI:43474, ChEBI:CHEBI:78515, ChEBI:CHEBI:142450;
COFACTOR	Name=Mg(2+); Xref=ChEBI:CHEBI:18420; Note=Binds 2 Mg(2+) ions, a primary Mg(2+) ion involved in positioning of the gamma-carbonyl group of the amino acid in Glu-tRNA(Gln), and a secondary transient Mg(2+) ion that participates in phosphoryl transfer by polarizing the gamma-phosphate group of ATP.
SUBUNIT	Component of the heterotrimeric GatCAB glutamyl-tRNA(Gln) amidotransferase complex composed of GatA, GatB and GatC.
DOMAIN	The N-terminal cradle domain recognizes the first base of the acceptor tRNA stem.
DOMAIN	The C-terminal tail domain, an anti-parallel amphiphilic helix bundle, is involved in discriminating and binding specific tRNAs. Probably recognizes the tRNA(Gln)-specific D-loop structure.
SIMILARITY	Belongs to the GatB/GatE family. GatB subfamily.

Keywords [?]

Gene Ontology [?]

GO:0030956; Cellular component:glutamyl-tRNA(Gln) amidotransferase complex

GO:0050567; Molecular function:glutaminyl-tRNA synthase (glutamine-hydrolyzing) activity

GO:0070681; Biological process:glutaminyl-tRNAGln biosynthesis via transamidation

GO:0006412; Biological process:translation

Cross-references [?]

Pfam	PF02934; GatB_N; 1;
Pfam	PF02637; GatB_Yqey; 1;
NCBIfam	TIGR00133; GatB; 1;
PROSITE	PS01234; GATB; 1;

Features [?]

From: GATB_STAAM (P64201)

Key

From

Description

Tag

Condition

FTGroup

REGION

Nter

294

/note="Cradle"

REGION

412

Cter

/note="Tail"

BINDING

/ligand="Mg(2+)"
/ligand_id="ChEBI:CHEBI:18420"
/ligand_label="2"

BINDING

/ligand="Mg(2+)"
/ligand_id="ChEBI:CHEBI:18420"
/ligand_label="1"

BINDING

124

/ligand="Mg(2+)"
/ligand_id="ChEBI:CHEBI:18420"
/ligand_label="1"

BINDING

150

/ligand="Mg(2+)"
/ligand_id="ChEBI:CHEBI:18420"
/ligand_label="1"

BINDING

153

/ligand="ATP"
/ligand_id="ChEBI:CHEBI:30616"

[ST]

BINDING

192

/ligand="Mg(2+)"
/ligand_id="ChEBI:CHEBI:18420"
/ligand_label="2"

BINDING

196

/ligand="ATP"
/ligand_id="ChEBI:CHEBI:30616"

BINDING

206

/ligand="ATP"
/ligand_id="ChEBI:CHEBI:30616"

BINDING

208

/ligand="ATP"
/ligand_id="ChEBI:CHEBI:30616"

[KR]

BINDING

210

/ligand="Mg(2+)"
/ligand_id="ChEBI:CHEBI:18420"
/ligand_label="2"

Additional information [?]

Size range	449-517 amino acids
Related rules	MF_00588
Fusion	Nter: MF_00126 (glnS) Cter: None

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