Recently, we reported a useful assay for the determination of yeast Hsp90 ATPase activity. Using this assay, high-throughput screening of similar to 10,000 compounds was performed to determine the feasibility of this assay on large scale. Results from high-throughput screening indicated that the assay was reproducible (av Z-factor = 0.80) and identified 0.57% of the compounds as Hsp90 inhibitors that exhibited IC(50)s less than 20 mu M. The structures of several of these inhibitory scaffolds are reported along with their IC50 values. (c) 2006 Elsevier Ltd. All rights reserved.