All KlPdr5p substrates bind to the same binding site(s) in the binding pocket. Growth inhibition zones of pdr5– and PDR5+ K. lactis cells exposed to (A) MTAE (1 mM), (B) TI (0.1 mM) and (C) TBT (0.9 M). The concentration-dependent inhibitory effect of (D) MTAE, (E) TI and (F) TBT on Pdr5p-mediated probe transport in K. lactis cells, calculated according to Eq. 1. Means and SDs were calculated from four independent repeats. (G) Growth inhibition zones of the PDR5+ K. lactis strain exposed to azoles and their respective combinations with and without the addition of the fluorescent probe diS-C3(3) (1 mM). Stock solutions of azoles: clotrimazole (0.01 mM), miconazole (0.02 mM), ketoconazole (0.03 mM), itraconazole (0.1 mM) and bifonazole (0.2 mM). (H) Schematic illustration of the same binding site(s) of all tested substrates in the KlPdr5p binding pocket.
