2DTD

Structure of Thermoplasma acidophilum aldohexose dehydrogenase (AldT) in ligand-free form


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.219 
  • R-Value Work: 0.189 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural Insights into Unique Substrate Selectivity of Thermoplasma acidophilumd-Aldohexose Dehydrogenase

Yasutake, Y.Nishiya, Y.Tamura, N.Tamura, T.

(2007) J.Mol.Biol. 367: 1034-1046

  • DOI: 10.1016/j.jmb.2007.01.029
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The D-aldohexose dehydrogenase from the thermoacidophilic archaea Thermoplasma acidophilum (AldT) belongs to the short-chain dehydrogenase/reductase (SDR) superfamily and catalyzes the oxidation of several monosaccharides with a preference for NAD(+) ...

    The D-aldohexose dehydrogenase from the thermoacidophilic archaea Thermoplasma acidophilum (AldT) belongs to the short-chain dehydrogenase/reductase (SDR) superfamily and catalyzes the oxidation of several monosaccharides with a preference for NAD(+) rather than NADP(+) as a cofactor. It has been found that AldT is a unique enzyme that exhibits the highest dehydrogenase activity against D-mannose. Here, we describe the crystal structures of AldT in ligand-free form, in complex with NADH, and in complex with the substrate D-mannose, at 2.1 A, 1.65 A, and 1.6 A resolution, respectively. The AldT subunit forms a typical SDR fold with an unexpectedly long C-terminal tail and assembles into an intertwined tetramer. The D-mannose complex structure reveals that Glu84 interacts with the axial C2 hydroxyl group of the bound D-mannose. Structural comparison with Bacillus megaterium glucose dehydrogenase (BmGlcDH) suggests that the conformation of the glutamate side-chain is crucial for discrimination between D-mannose and its C2 epimer D-glucose, and the conformation of the glutamate side-chain depends on the spatial arrangement of nearby hydrophobic residues that do not directly interact with the substrate. Elucidation of the D-mannose recognition mechanism of AldT further provides structural insights into the unique substrate selectivity of AldT. Finally, we show that the extended C-terminal tail completely shuts the substrate-binding pocket of the neighboring subunit both in the presence and absence of substrate. The elaborate inter-subunit interactions between the C-terminal tail and the entrance of the substrate-binding pocket imply that the tail may play a pivotal role in the enzyme activity.


    Organizational Affiliation

    Research Institute of Genome-based Biofactory, National Institute of Advanced Industrial Science and Technology, Toyohira-ku, Sapporo 062-8517, Japan.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Glucose 1-dehydrogenase related protein
A, B
264Thermoplasma acidophilum (strain ATCC 25905 / DSM 1728 / JCM 9062 / NBRC 15155 / AMRC-C165)Mutation(s): 0 
Find proteins for Q9HK51 (Thermoplasma acidophilum (strain ATCC 25905 / DSM 1728 / JCM 9062 / NBRC 15155 / AMRC-C165))
Go to UniProtKB:  Q9HK51
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A, B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.219 
  • R-Value Work: 0.189 
  • Space Group: P 32 2 1
Unit Cell:
Length (Å)Angle (°)
a = 81.830α = 90.00
b = 81.830β = 90.00
c = 138.509γ = 120.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
CNSrefinement
DENZOdata reduction
AMoREphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-03-27
    Type: Initial release
  • Version 1.1: 2008-04-30
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Version format compliance