Ansamycin antibiotic compound that inhibits Hsp90 activity (IC 50 = 2 μ M) by binding to the ATP-binding site. Exhibits antitumor and cytocidal activities (IC 50 ~ 0.4 μ M) by causing degradation of key oncogenic client proteins such as ErbB2 and cRaf1. Displays higher affinity and potency than geldanamycin (9,13-Dihydroxy-8,14,19-trimethoxy-4,10,12,16-tetramethyl-2-azabicyclo[16.3.1]docosa-4,6,10,18,21-pentaene-3,20,22-trione, 9-carbamate ).
