PDBsum entry 4is4

Go to PDB code: 
protein Protein-protein interface(s) links
Ligase PDB id
Jmol PyMol
Protein chains
339 a.a.
(+ 3 more) 306 a.a.
Waters ×969
PDB id:
Name: Ligase
Title: The glutamine synthetase from the dicotyledonous plant m. Tr is a decamer
Structure: Glutamine synthetase. Chain: a, b, c, d, e, f, g, h, i, j. Engineered: yes
Source: Medicago truncatula. Barrel medic. Organism_taxid: 3880. Gene: mtr_6g071070. Expressed in: escherichia coli. Expression_system_taxid: 562
2.35Å     R-factor:   0.177     R-free:   0.217
Authors: A.R.Seabra,H.Carvalho,P.J.B.Pereira
Key ref: E.Torreira et al. (2014). The structures of cytosolic and plastid-located glutamine synthetases from Medicago truncatula reveal a common and dynamic architecture. Acta Crystallogr D Biol Crystallogr, 70, 981-993. PubMed id: 24699643 DOI: 10.1107/S1399004713034718
16-Jan-13     Release date:   09-Apr-14    
Go to PROCHECK summary

Protein chain
Pfam   ArchSchema ?
O04998  (O04998_MEDTR) -  Glutamine synthetase
356 a.a.
339 a.a.
Protein chains
Pfam   ArchSchema ?
O04998  (O04998_MEDTR) -  Glutamine synthetase
356 a.a.
306 a.a.
Key:    PfamA domain  Secondary structure

 Enzyme reactions 
   Enzyme class: Chains A, B, C, D, E, F, G, H, I, J: E.C.  - Glutamine synthetase.
[IntEnz]   [ExPASy]   [KEGG]   [BRENDA]
      Reaction: ATP + L-glutamate + NH3 = ADP + phosphate + L-glutamine
+ L-glutamate
+ NH(3)
+ phosphate
+ L-glutamine
Molecule diagrams generated from .mol files obtained from the KEGG ftp site
 Gene Ontology (GO) functional annotation 
  GO annot!
  Biological process     nitrogen compound metabolic process   2 terms 
  Biochemical function     nucleotide binding     4 terms  


DOI no: 10.1107/S1399004713034718 Acta Crystallogr D Biol Crystallogr 70:981-993 (2014)
PubMed id: 24699643  
The structures of cytosolic and plastid-located glutamine synthetases from Medicago truncatula reveal a common and dynamic architecture.
E.Torreira, A.R.Seabra, H.Marriott, M.Zhou, ├.ô.Llorca, C.V.Robinson, H.G.Carvalho, C.Fernández-Tornero, P.J.Pereira.
The first step of nitrogen assimilation in higher plants, the energy-driven incorporation of ammonia into glutamate, is catalyzed by glutamine synthetase. This central process yields the readily metabolizable glutamine, which in turn is at the basis of all subsequent biosynthesis of nitrogenous compounds. The essential role performed by glutamine synthetase makes it a prime target for herbicidal compounds, but also a suitable intervention point for the improvement of crop yields. Although the majority of crop plants are dicotyledonous, little is known about the structural organization of glutamine synthetase in these organisms and about the functional differences between the different isoforms. Here, the structural characterization of two glutamine synthetase isoforms from the model legume Medicago truncatula is reported: the crystallographic structure of cytoplasmic GSII-1a and an electron cryomicroscopy reconstruction of plastid-located GSII-2a. Together, these structural models unveil a decameric organization of dicotyledonous glutamine synthetase, with two pentameric rings weakly connected by inter-ring loops. Moreover, rearrangement of these dynamic loops changes the relative orientation of the rings, suggesting a zipper-like mechanism for their assembly into a decameric enzyme. Finally, the atomic structure of M. truncatula GSII-1a provides important insights into the structural determinants of herbicide resistance in this family of enzymes, opening new avenues for the development of herbicide-resistant plants.