Crystal Structure of ROK Hexokinase from Thermus thermophilus

Experimental Data Snapshot

  • Resolution: 2.02 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.181 
  • R-Value Observed: 0.183 

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Characterization and crystal structure of the thermophilic ROK hexokinase from Thermus thermophilus

Nakamura, T.Kashima, Y.Mine, S.Oku, T.Uegaki, K.

(2012) J Biosci Bioeng 

  • DOI: https://doi.org/10.1016/j.jbiosc.2012.03.018
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    We characterized and determined the crystal structure of a putative glucokinase/hexokinase from Thermus thermophilus that belongs to the ROK (bacterial repressors, uncharacterized open reading frames, and sugar kinases) family. The protein possessed significant enzymatic activity against glucose and mannose, with V(max) values of 260 and 68 μmol·min(-1)·mg(-1) protein, respectively. Therefore, we concluded that the enzyme is a hexokinase. However, the hexokinase showed little catalytic capacity for galactose and fructose. Circular dichroism measurements indicated that the enzyme was structurally stable at 90°C. The crystal structure of the enzyme was determined at a resolution of 2.02 Å, with R(cryst) and R(free) values of 18.1% and 22.6%, respectively. The polypeptide structure was divided into large and small domains. The ROK consensus sequences 1 and 2 were included in the large domain. The cysteine-rich consensus sequence 2 folded into a zinc finger, and the bound zinc was confirmed by both electron density and X-ray absorption fine structure (XAFS) spectrum. The overall structure was a homotetramer that consisted of a dimer of dimers. The accessible surface area buried by the association of the dimers into the tetrameric structures was significantly higher in the T. thermophilus enzyme than in a homologous tetrameric ROK sugar kinase.

  • Organizational Affiliation

    National Institute of Advanced Industrial Science and Technology (AIST), Ikeda, Osaka, Japan.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B, C, D
302Thermus thermophilus HB8Mutation(s): 0 
Gene Names: TTHA0299
Find proteins for Q5SLJ4 (Thermus thermophilus (strain ATCC 27634 / DSM 579 / HB8))
Explore Q5SLJ4 
Go to UniProtKB:  Q5SLJ4
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ5SLJ4
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.02 Å
  • R-Value Free: 0.225 
  • R-Value Work: 0.181 
  • R-Value Observed: 0.183 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 70.926α = 90
b = 138.144β = 95.41
c = 75.156γ = 90
Software Package:
Software NamePurpose
HKL-2000data collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-06-27
    Type: Initial release