Structures of alternatively spliced isoforms of human ketohexokinase.
Trinh, C.H., Asipu, A., Bonthron, D.T., Phillips, S.E.(2009) Acta Crystallogr D Biol Crystallogr 65: 201-211
- PubMed: 19237742 
- DOI: https://doi.org/10.1107/S0907444908041115
- Primary Citation of Related Structures:  
2HQQ, 2HW1 - PubMed Abstract: 
A molecular understanding of the unique aspects of dietary fructose metabolism may be the key to understanding and controlling the current epidemic of fructose-related obesity, diabetes and related adverse metabolic states in Western populations. Fructose catabolism is initiated by its phosphorylation to fructose 1-phosphate, which is performed by ketohexokinase (KHK). Here, the crystal structures of the two alternatively spliced isoforms of human ketohexokinase, hepatic KHK-C and the peripheral isoform KHK-A, and of the ternary complex of KHK-A with the substrate fructose and AMP-PNP are reported. The structure of the KHK-A ternary complex revealed an active site with both the substrate fructose and the ATP analogue in positions ready for phosphorylation following a reaction mechanism similar to that of the pfkB family of carbohydrate kinases. Hepatic KHK deficiency causes the benign disorder essential fructosuria. The effects of the disease-causing mutations (Gly40Arg and Ala43Thr) have been modelled in the context of the KHK structure.
Organizational Affiliation: 
Astbury Centre for Structural Molecular Biology, Institute of Molecular and Cellular Biology, University of Leeds, Leeds, England.