Results of competitive binding assay using the fluorescent ATP analogue bis-ANS. To identify E. histolytica Hsp90-specific inhibitors, bis-ANS was used for binding assay with the E. histolytica Hsp90 ATP-binding domain preincubated in the presence of DMSO or 100 nM Hsp90 inhibitors (SMDC-304198, 304201, 304203, 304209, and SNX-2112). Values represent means and standard errors of the means of duplicate readings. *, P = 0.0187, Student's t test.