Bafilomycin and Concanamycin Derivatives as Specific Inhibitors of P- and V-Type ATPases

Abstract

The bafilomycins, unusual macrolide antibiotics with a 16-membered lactone ring, were isolated from Streptomyces griseus (6). Recently, in a detailed analysis we compared the effects of bafilomycin A₁ (1) (Figure 1) on representative enzymes of the three classes of membrane bound ion-translocating ATPases (2). F₁Fo ATPases (F-type) from bacteria and mitochondria are not affected by this antibiotic. In contrast, P-type ATPases are moderately sensitive (micromolar concentrations) to this inhibitor. However, V-type ATPases from Neurospora vacuoles, chromaffin granules and plant vacuoles are extremely sensitive (nanomolar concentrations). For the first time these results showed convincingly that bafilomycin A₁ (1) is useful for distinguishing among the different types of ATPases and that it is a potent, relatively specific inhibitor of the vacuolar ATPases (2). Here, we show that the concanamycins, which contain an 18membered lactone ring (5), and which are structurally related to the bafilomycins (Figure 1), are also useful for distinguishing among the different ATPases and are even more specific inhibitors of V-type ATPases.