Fig 3. Complementation of the caffeine sensitivity of ppz1 S. cerevisiae cells by the expression of mutant CaPpz1 proteins.

Wild type BY4741 S. cerevisiae strain or its isogenic ppz1 deletion mutant strain were transformed with empty plasmids as a negative control. The mutant strain was also transformed with YCplac111 (A) or YEplac181 (B) carrying wild type or mutant CaPPZ1 inserts (that are labeled by the names of the encoded proteins). Yeast cells were plated on YPD in the absence or in the presence of increasing concentrations of caffeine and the growth rate of the yeast cells was determined in spot tests. 3 x 10³ and 3 x 10² cells were spotted on YPD plates, which were photographed after 72 h incubation. Representative results of 3 independent experiments are shown.