Figure 1.

(a) Screening of VmFbpA inhibitors for Fe³⁺ binding. The gray bar represents the remaining Fe concentration after treatment with the extracts of 20 spices; 10 mM EDTA was used as the negative control. In addition, apo VmFbpA (Apo) and Fe³⁺-VmFbpA (Holo) were also measured for comparison. Buffer represents the gel filtration buffer (50 mM Tris-HCl (pH 8.0), 50 mM NaHCO₃, and 150 mM NaCl) used in VmFbpA purification. Data are means ± SD. Means with the same letter are not significantly different from each other (p < 0.05) (b) Eluents after inhibition assays using cinnamon extracts. (c) Absorbance spectra (300–700 nm) of the respective eluents shown in (b). (d) Eluents after inhibition assays using rosemary extracts. (e) Absorbance spectra (300–700 nm) of the respective eluents shown in (c). Spectra of apo and Fe³⁺-VmFbpA (controls). (f) Absorbance spectra (300–700 nm) of RA binding to apo VmFbpA. (g) Absorbance spectra (300–700 nm) of RA only. Base is elution buffer containing 50 mM Tris-HCl (pH 8.0), 50 mM NaHCO₃, 150 mM NaCl, and 250 mM imidazole.