PROSITE documentation PDOC51986
Glutamine synthetase (GS) beta-grasp and catalytic domains profiles


The glutamine synthetases (GSs; EC, also known as γ-glutamyl: ammonia ligases) are a family of large oligomeric enzymes catalyzing the condensation of ammonium and glutamate, along with ATP, to form glutamine, the principal source of nitrogen for protein and nucleic acid synthesis. Because of their critical role in nitrogen metabolism, these enzymes are found in all forms of life from primitive to higher organisms, and they may be among the most ancient functioning enzymes in existence. In mammals, the activity eliminates cytotoxic ammonia, at the same time converting neurotoxic glutamate to harmless glutamine; there are a number of links between changes in GS activity and neurodegenerative disorders, such as Alzheimer's disease. In plants, because of its importance in the assimilation and re-assimilation of ammonia, the enzyme is a target of some herbicides. GS is also a central component of bacterial nitrogen metabolism and a potential drug target [1,2,3,4,5,6,7,8].

The GS family can be divided into three main enzyme types, easily distinguished by length: GSI with 360 amino acids on average, GSII with 450, and GSIII with 730. All of them form multimeric proteins containing double-ringed quaternary structures composed of identical units: GSI- and GSIII-type enzymes contain 12 identical subunits, whereas GSII- enzymes contain 10 identical subunits consisting of 2 pentameric rings. All three GS classes contain a homology region that consists of a regulatory N-terminal β-grasp domain and a catalytic C-terminal domain, with the N-terminal domain of one subunit and the C-terminal domain of the neighboring subunit forming an active site. The β-grasp domain consists of a five-strand antiparallel β-sheet (see <PDB:3FKY>) whereas the catalytic domain contains an eight-stranded β-sheet (see <PDB:7CPR>) [1,2,3,4,5,6,7,8].

The profiles we developed cover the entire GS β-grasp and catalytic domains.

Last update:

February 2023 / Profile revised.


Technical section

PROSITE methods (with tools and information) covered by this documentation:

GS_BETA_GRASP, PS51986; Glutamine synthetase (GS) beta-grasp domain profile  (MATRIX)

GS_CATALYTIC, PS51987; Glutamine synthetase (GS) catalytic domain profile  (MATRIX)


1AuthorsWyatt K. White H.E. Wang L. Bateman O.A. Slingsby C. Orlova E.V. Wistow G.
TitleLengsin is a survivor of an ancient family of class I glutamine synthetases re-engineered by evolution for a role in the vertebrate lens.
SourceStructure 14:1823-1834(2006).
PubMed ID17161372

2AuthorsUnno H. Uchida T. Sugawara H. Kurisu G. Sugiyama T. Yamaya T. Sakakibara H. Hase T. Kusunoki M.
TitleAtomic structure of plant glutamine synthetase: a key enzyme for plant productivity.
SourceJ. Biol. Chem. 281:29287-29296(2006).
PubMed ID16829528

3AuthorsHe Y.-X. Gui L. Liu Y.-Z. Du Y. Zhou Y. Li P. Zhou C.-Z.
TitleCrystal structure of Saccharomyces cerevisiae glutamine synthetase Gln1 suggests a nanotube-like supramolecular assembly.
SourceProteins 76:249-254(2009).
PubMed ID19322816

4Authorsvan Rooyen J.M. Abratt V.R. Belrhali H. Sewell T.
TitleCrystal structure of Type III glutamine synthetase: surprising reversal of the inter-ring interface.
SourceStructure 19:471-483(2011).
PubMed ID21481771

5AuthorsQiu C. Hong Y. Cao Y. Wang F. Fu Z. Shi Y. Wei M. Liu S. Lin J.
TitleMolecular cloning and characterization of glutamine synthetase, a tegumental protein from Schistosoma japonicum.
SourceParasitol. Res. 111:2367-2376(2012).
PubMed ID23011789

6AuthorsWagner D. Wiemann P. Huss K. Brandt U. Fleissner A. Tudzynski B.
TitleA sensing role of the glutamine synthetase in the nitrogen regulation network in Fusarium fujikuroi.
SourcePLoS One. 8:E80740-E80740(2013).
PubMed ID24260467

7AuthorsLee B.N. Adams T.H.
TitleThe Aspergillus nidulans fluG gene is required for production of an extracellular developmental signal and is related to prokaryotic glutamine synthetase I.
SourceGenes. Dev. 8:641-651(1994).
PubMed ID7926755

8AuthorsKurihara S. Oda S. Tsuboi Y. Kim H.G. Oshida M. Kumagai H. Suzuki H.
Titlegamma-Glutamylputrescine synthetase in the putrescine utilization pathway of Escherichia coli K-12.
SourceJ. Biol. Chem. 283:19981-19990(2008).
PubMed ID18495664

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