2Q2R

Trypanosoma cruzi glucokinase in complex with beta-D-glucose and ADP


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.258 
  • R-Value Work: 0.194 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

The Crystal Structure of Trypanosoma cruzi Glucokinase Reveals Features Determining Oligomerization and Anomer Specificity of Hexose-phosphorylating Enzymes.

Cordeiro, A.T.Caceres, A.J.Vertommen, D.Concepcion, J.L.Michels, P.A.Versees, W.

(2007) J.Mol.Biol. 372: 1215-1226

  • DOI: 10.1016/j.jmb.2007.07.021

  • PubMed Abstract: 
  • Glucose is an essential substrate for Trypanosoma cruzi, the protozoan organism responsible for Chagas' disease. The glucose is intracellularly phosphorylated to glucose 6-phosphate. Previously, a hexokinase responsible for this phosphorylation has b ...

    Glucose is an essential substrate for Trypanosoma cruzi, the protozoan organism responsible for Chagas' disease. The glucose is intracellularly phosphorylated to glucose 6-phosphate. Previously, a hexokinase responsible for this phosphorylation has been characterized. Recently, we identified an ATP-dependent glucokinase in T. cruzi exhibiting a tenfold lower substrate affinity compared to the hexokinase. Both enzymes, which belong to very different groups of the same family, are located inside glycosomes, the peroxisome-like organelles of Kinetoplastida that are known to contain the first seven glycolytic steps as well as enzymes of the oxidative branch of the pentose phosphate pathway. Here, we present the crystallographic structure of T. cruzi glucokinase, in complex with glucose and ADP. The structure suggests a loose tetrameric assembly formed by the association of two tight dimers. TcGlcK was previously reported to exist in a concentration-dependent equilibrium of monomeric and dimeric states. Here, we used mass spectrometry analysis to confirm the existence of TcGlcK monomeric and dimeric states. The analysis of subunit interactions and comparison with the bacterial glucokinases give insights into the forces promoting the stability of the different oligomeric states. Each T. cruzi glucokinase monomer contains one glucose and one ADP molecule. In contrast to hexokinases, which show a moderate preference for the alpha anomer of glucose, the electron density clearly shows the d-glucose bound in the beta configuration in the T.cruzi glucokinase. Kinetic assays with alpha and beta-d-glucose further confirm a moderate preference of the T. cruzi glucokinase for the beta anomer. Structural comparison of the glucokinase and hexokinases permits the identification of a possible mechanism for anomer selectivity in these hexose-phosphorylating enzymes. The preference for distinct anomers suggests that in T. cruzi hexokinase and glucokinase are not directly competing for the same substrate and are probably both present because they exert distinct physiological functions.


    Organizational Affiliation

    Research Unit for Tropical Diseases, Christian de Duve Institute of Cellular Pathology, Avenue Hippocrate 74, B-1200 Brussels, Belgium.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Glucokinase 1, putative
A, B
373Trypanosoma cruzi (strain CL Brener)Mutation(s): 0 
EC: 2.7.1.2
Find proteins for Q4E4E1 (Trypanosoma cruzi (strain CL Brener))
Go to UniProtKB:  Q4E4E1
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ADP
Query on ADP

Download SDF File 
Download CCD File 
A, B
ADENOSINE-5'-DIPHOSPHATE
C10 H15 N5 O10 P2
XTWYTFMLZFPYCI-KQYNXXCUSA-N
 Ligand Interaction
BGC
Query on BGC

Download SDF File 
Download CCD File 
A, B
BETA-D-GLUCOSE
C6 H12 O6
WQZGKKKJIJFFOK-VFUOTHLCSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.258 
  • R-Value Work: 0.194 
  • Space Group: P 21 21 2
Unit Cell:
Length (Å)Angle (°)
a = 107.937α = 90.00
b = 125.697β = 90.00
c = 65.112γ = 90.00
Software Package:
Software NamePurpose
REFMACrefinement
DENZOdata reduction
SCALEPACKdata scaling
SHARPphasing
HKL-2000data collection

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-10-16
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Derived calculations, Version format compliance