Crystal structure of a fructokinase homolog from Halothermothrix orenii.

Teck Khiang Chua, J Seetharaman, Joanna M Kasprzak, Cherlyn Ng, Bharat K C Patel, Christopher Love, Janusz M Bujnicki, J Sivaraman

Department of Biological Sciences, 14 Science Drive 4, National University of Singapore, Singapore 117543, Singapore.

Journal of structural biology 2010 Sep

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Fructokinase (FRK; EC 2.7.1.4) catalyzes the phosphorylation of d-fructose to d-fructose 6-phosphate (F6P). This irreversible and near rate-limiting step is a central and regulatory process in plants and bacteria, which channels fructose into a metabolically active state for glycolysis. Towards understanding the mechanism of FRK, here we report the crystal structure of a FRK homolog from a thermohalophilic bacterium Halothermothrixorenii (Hore_18220 in sequence databases). The structure of the Hore_18220 protein reveals a catalytic domain with a Rossmann-like fold and a beta-sheet "lid" for dimerization. Based on comparison of Hore_18220 to structures of related proteins, we propose its mechanism of action, in which the lid serves to regulate access to the substrate binding sites. Close relationship of Hore_18220 and plant FRK enzymes allows us to propose a model for the structure and function of FRKs. Copyright 2010 Elsevier Inc. All rights reserved.

Citation

Teck Khiang Chua, J Seetharaman, Joanna M Kasprzak, Cherlyn Ng, Bharat K C Patel, Christopher Love, Janusz M Bujnicki, J Sivaraman. Crystal structure of a fructokinase homolog from Halothermothrix orenii. Journal of structural biology. 2010 Sep;171(3):397-401