National Center for
4EGK: Human Hsp90-alpha Atpase Domain Bound to Radicicol
Fragment screening using capillary electrophoresis (CEfrag) for hit identification of heat shock protein 90 ATPase inhibitors
J Biomol Screen (2012) 17 p.868-876
CEfrag is a new fragment screening technology based on affinity capillary electrophoresis (ACE). Here we report on the development of a mobility shift competition assay using full-length human heat shock protein 90alpha (Hsp90alpha), radicicol as the competitor probe ligand, and successful screening of the Selcia fragment library. The CEfrag assay was able to detect weaker affinity (IC(50) >500 microM) fragments than were detected by a fluorescence polarization competition assay using FITC-labeled geldanamycin. The binding site of selected fragments was determined by co-crystallization with recombinant Hsp90alpha N-terminal domain and X-ray analysis. The results of this study confirm that CEfrag is a sensitive microscale technique enabling detection of fragments binding to the biological target in near-physiological solution.