A. fulgidus GlnK3, ligand-free

Experimental Data Snapshot

  • Resolution: 1.82 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.207 
  • R-Value Observed: 0.209 

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This is version 1.3 of the entry. See complete history


Mechanism of disruption of the Amt-GlnK complex by P(II)-mediated sensing of 2-oxoglutarate.

Maier, S.Schleberger, P.Lu, W.Wacker, T.Pfluger, T.Litz, C.Andrade, S.L.

(2011) PLoS One 6: e26327-e26327

  • DOI: https://doi.org/10.1371/journal.pone.0026327
  • Primary Citation of Related Structures:  
    3T9Z, 3TA0, 3TA1, 3TA2

  • PubMed Abstract: 

    GlnK proteins regulate the active uptake of ammonium by Amt transport proteins by inserting their regulatory T-loops into the transport channels of the Amt trimer and physically blocking substrate passage. They sense the cellular nitrogen status through 2-oxoglutarate, and the energy level of the cell by binding both ATP and ADP with different affinities. The hyperthermophilic euryarchaeon Archaeoglobus fulgidus possesses three Amt proteins, each encoded in an operon with a GlnK ortholog. One of these proteins, GlnK2 was recently found to be incapable of binding 2-OG, and in order to understand the implications of this finding we conducted a detailed structural and functional analysis of a second GlnK protein from A. fulgidus, GlnK3. Contrary to Af-GlnK2 this protein was able to bind both ATP/2-OG and ADP to yield inactive and functional states, respectively. Due to the thermostable nature of the protein we could observe the exact positioning of the notoriously flexible T-loops and explain the binding behavior of GlnK proteins to their interaction partner, the Amt proteins. A thermodynamic analysis of these binding events using microcalorimetry evaluated by microstate modeling revealed significant differences in binding cooperativity compared to other characterized P(II) proteins, underlining the diversity and adaptability of this class of regulatory signaling proteins.

  • Organizational Affiliation

    Institut für organische Chemie und Biochemie, Albert-Ludwigs-Universität Freiburg, Freiburg, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Nitrogen regulatory protein P-II (GlnB-3)
A, B, C, D, E
A, B, C, D, E, F
118Archaeoglobus fulgidus DSM 4304Mutation(s): 0 
Gene Names: AF_1750glnK3
Find proteins for O28524 (Archaeoglobus fulgidus (strain ATCC 49558 / DSM 4304 / JCM 9628 / NBRC 100126 / VC-16))
Explore O28524 
Go to UniProtKB:  O28524
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO28524
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on FLC

Download Ideal Coordinates CCD File 
C6 H5 O7
Experimental Data & Validation

Experimental Data

  • Resolution: 1.82 Å
  • R-Value Free: 0.236 
  • R-Value Work: 0.207 
  • R-Value Observed: 0.209 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 123.35α = 90
b = 92.76β = 133.58
c = 88.41γ = 90
Software Package:
Software NamePurpose
MAR345data collection
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-10-26
    Type: Initial release
  • Version 1.1: 2012-03-28
    Changes: Database references
  • Version 1.2: 2017-11-08
    Changes: Refinement description
  • Version 1.3: 2023-09-13
    Changes: Data collection, Database references, Derived calculations, Refinement description