4IS4

The glutamine synthetase from the dicotyledonous plant M. truncatula is a decamer


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.35 Å
  • R-Value Free: 0.217 
  • R-Value Work: 0.175 
  • R-Value Observed: 0.177 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

The structures of cytosolic and plastid-located glutamine synthetases from Medicago truncatula reveal a common and dynamic architecture.

Torreira, E.Seabra, A.R.Marriott, H.Zhou, M.Llorca, O.Robinson, C.V.Carvalho, H.G.Fernandez-Tornero, C.Pereira, P.J.

(2014) Acta Crystallogr D Biol Crystallogr 70: 981-993

  • DOI: 10.1107/S1399004713034718
  • Primary Citation of Related Structures:  
    4IS4

  • PubMed Abstract: 
  • 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 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.


    Related Citations: 
    • Crystallization and preliminary crystallographic characterization of glutamine synthetase from Medicago truncatula.
      Seabra, A.R., Carvalho, H., Pereira, P.J.
      (2009) Acta Crystallogr Sect F Struct Biol Cryst Commun 65: 1309

    Organizational Affiliation

    Biomolecular Structure Group, IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Glutamine synthetase
A, B, C, D, E, F, G, H
A, B, C, D, E, F, G, H, I, J
378Medicago truncatulaMutation(s): 0 
Gene Names: MTR_6g07107011427840MtrunA17_Chr6g0479141
EC: 6.3.1.2
UniProt
Find proteins for O04998 (Medicago truncatula)
Explore O04998 
Go to UniProtKB:  O04998
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

Unit Cell:
Length ( Å )Angle ( ˚ )
a = 99.335α = 90
b = 101.672β = 103.69
c = 188.084γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
PHASERphasing
PHENIXrefinement
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report




Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-04-09
    Type: Initial release
  • Version 1.1: 2014-09-24
    Changes: Database references