Structure of the effector-binding domain of the arabinose repressor AraR from Bacillus subtilis.
Prochazkova, K., Cermakova, K., Pachl, P., Sieglova, I., Fabry, M., Otwinowski, Z., Rezacova, P.(2012) Acta Crystallogr D Biol Crystallogr 68: 176-185
- PubMed: 22281747 
- DOI: https://doi.org/10.1107/S090744491105414X
- Primary Citation of Related Structures:  
3TB6 - PubMed Abstract: 
In Bacillus subtilis, the arabinose repressor AraR negatively controls the expression of genes in the metabolic pathway of arabinose-containing polysaccharides. The protein is composed of two domains of different phylogenetic origin and function: an N-terminal DNA-binding domain belonging to the GntR family and a C-terminal effector-binding domain that shows similarity to members of the GalR/LacI family. The crystal structure of the C-terminal effector-binding domain of AraR in complex with the effector L-arabinose has been determined at 2.2 Å resolution. The L-arabinose binding affinity was characterized by isothermal titration calorimetry and differential scanning fluorimetry; the K(d) value was 8.4 ± 0.4 µM. The effect of L-arabinose on the protein oligomeric state was investigated in solution and detailed analysis of the crystal identified a dimer organization which is distinctive from that of other members of the GalR/LacI family.
Organizational Affiliation: 
Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, Prague 6, Czech Republic.