Structure of human Eg5 in complex with a new monastrol-based inhibitor bound in the R configuration

Garcia-Saez, I., DeBonis, S., Lopez, R., Trucco, F., Rousseau, B., Thuery, P. and Kozielski, F. (2007) Structure of human Eg5 in complex with a new monastrol-based inhibitor bound in the R configuration. Journal of Biological Chemistry, 282(13), pp. 9740-9747. (doi: 10.1074/jbc.M608883200)

Abstract

Drugs that target mitotic spindle proteins have been proven useful for tackling tumor growth. Eg5, a kinesin-5 family member, represents a potential target, since its inhibition leads to prolonged mitotic arrest through the activation of the mitotic checkpoint and apoptotic cell death. Monastrol, a specific dihydropyrimidine inhibitor of Eg5, shows stereo-specificity, since predominantly the (S)-, but not the (R)-, enantiomer has been shown to be the biologically active compound in vitro and in cell-based assays. Here, we solved the crystal structure (2.7 angstrom) of the complex between human Eg5 and a new keto derivative of monastrol (named mon-97), a potent antimitotic inhibitor. Surprisingly, we identified the (R)-enantiomer bound in the active site, and not, as for monastrol, the (S)-enantiomer. The absolute configuration of this more active (R)-enantiomer has been unambiguously determined via chemical correlation and x-ray analysis. Unexpectedly, both the R- and the S-forms inhibit Eg5 ATPase activity with IC50 values of 110 and 520 nM (basal assays) and 150 nm and 650 nm (microtubule-stimulated assays), respectively. However, the difference was large enough for the protein to select the (R)- over the (S)-enantiomer. Taken together, these results show that in this new monastrol family, both (R)- and (S)-enantiomers can be active as Eg5 inhibitors. This considerably broadens the alternatives for rational drug design.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Kozielski, Professor Frank
• Authors: Garcia-Saez, I., DeBonis, S., Lopez, R., Trucco, F., Rousseau, B., Thuery, P., and Kozielski, F.
• College/School: College of Medical Veterinary and Life Sciences > School of Cancer Sciences
• Journal Name: Journal of Biological Chemistry
• Journal Abbr.: J Biol Chem.
• Publisher: American Society for Biochemistry and Molecular Biology, Inc.
• ISSN: 0021-9258
• ISSN (Online): 1083-351X