Fig. 4. Comparison of GBD–Zap1 and myc-Zap1 activities in response to a range of zinc concentrations. (A) A zap1 mutant strain (ZHY6) bearing the pDg2 ZRE-lacZ reporter and pGBD–Zap1_1–880 (filled squares), pGBD–Zap1_Δ553–686 (filled diamonds) or pGBD–Zap1_552–880 (open circles) was grown to exponential phase in LZM supplemented with the indicated concentrations of ZnCl₂ prior to assay for β-galactosidase activity. (B) The same zap1 mutant strain bearing the pDg2 ZRE-lacZ reporter and pMyc-Zap1_1–880 (filled squares), pMyc-Zap1_Δ553–686 (filled diamonds) or pMyc-Zap1_552–880 (open circles) was grown to exponential phase in LZM supplemented with the indicated concentrations of ZnCl₂ prior to assay for β-galactosidase activity. Shown are representative experiments in which the standard deviations were <10% of the corresponding mean.