2VNC

Crystal structure of Glycogen Debranching enzyme TreX from Sulfolobus solfataricus


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 3 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.215 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural Insight Into the Bifunctional Mechanism of the Glycogen-Debranching Enzyme Trex from the Archaeon Sulfolobus Solfataricus.

Woo, E.-J.Lee, S.Cha, H.Park, J.-T.Yoon, S.-M.Song, H.-M.Park, K.-H.

(2008) J.Biol.Chem. 283: 28641

  • DOI: 10.1074/jbc.M802560200
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • TreX is an archaeal glycogen-debranching enzyme that exists in two oligomeric states in solution, as a dimer and tetramer. Unlike its homologs, TreX from Sulfolobus solfataricus shows dual activities for alpha-1,4-transferase and alpha-1,6-glucosidas ...

    TreX is an archaeal glycogen-debranching enzyme that exists in two oligomeric states in solution, as a dimer and tetramer. Unlike its homologs, TreX from Sulfolobus solfataricus shows dual activities for alpha-1,4-transferase and alpha-1,6-glucosidase. To understand this bifunctional mechanism, we determined the crystal structure of TreX in complex with an acarbose ligand. The acarbose intermediate was covalently bound to Asp363, occupying subsites -1 to -3. Although generally similar to the monomeric structure of isoamylase, TreX exhibits two different active-site configurations depending on its oligomeric state. The N terminus of one subunit is located at the active site of the other molecule, resulting in a reshaping of the active site in the tetramer. This is accompanied by a large shift in the "flexible loop" (amino acids 399-416), creating connected holes inside the tetramer. Mutations in the N-terminal region result in a sharp increase in alpha-1,4-transferase activity and a reduced level of alpha-1,6-glucosidase activity. On the basis of geometrical analysis of the active site and mutational study, we suggest that the structural lid (acids 99-97) at the active site generated by the tetramerization is closely associated with the bifunctionality and in particular with the alpha-1,4-transferase activity. These results provide a structural basis for the modulation of activities upon TreX oligomerization that may represent a common mode of action for other glycogen-debranching enzymes in higher organisms.


    Organizational Affiliation

    Translational Research Center, Korea Research Institute of Bioscience and Biotechnology, 111 Gwahangno, Yuseong-gu, Daejeon 305-806.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
GLYCOGEN OPERON PROTEIN GLGX
A, B
718Sulfolobus solfataricusMutation(s): 0 
Gene Names: orf c06021
Find proteins for P95868 (Sulfolobus solfataricus)
Go to UniProtKB:  P95868
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 3 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.215 
  • Space Group: P 31 2 1
Unit Cell:
Length (Å)Angle (°)
a = 136.077α = 90.00
b = 136.077β = 90.00
c = 173.545γ = 120.00
Software Package:
Software NamePurpose
REFMACrefinement
PHASERphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-07-29
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance