Fig. 4: The HRFWH motif is essential for Candida albicans growth under zinc restriction at neutral pH.

a–f Wild type (Wt), PRA1 deletion mutant (pra1∆), pra1∆ expressing wild type PRA1 (pra1∆+PRA1) and pra1∆ expressing 178-HRFWH-182 His-to-Ala variant (pra1∆+PRA1^His-to-Ala) were cultured in acidic (unbuffered, starting pH ~5) or neutral/alkaline (buffered to pH 7.4) zinc-free minimal medium (YNB-zinc-dropout; 0.5% glucose) supplemented with 1 μM zinc. To elicit mild- and strong-zinc depletion, media were supplemented with 0.5 mM or 2 mM EDTA, respectively. Cells were cultured at 30 °C and 180 rpm. Growth was assessed by measuring OD₆₀₀ for 11 days (n = 8). Results are the mean of four independent experiments. The data points represent the mean, and the error bars represent the standard deviation. Dark red circles represent Wt, red triangles represent pra1∆, inverted yellow triangles represent (pra1∆+PRA1), and orange diamonds represent (pra1∆+PRA1^His-to-Ala) strains. g The area under the curve was calculated for each growth curve and plotted with magenta coloring for high and cyan coloring for low measurements. Source data are provided as a Source Data file.