Figure 4.

Binding of propiconazole to CYP90D1. Recombinant CYP90D1 (3.5 μM) was dissolved in 50 mM sodium phosphate buffer (pH 7.0) with 0.1% Tween 20 containing 20% glycerol, and Pcz was added to CYP90D1 at a final concentration of 3.5 μM (A). Spectrophotometric titration of CYP90D1 with Pcz induced spectral changes in CYP90D1. Pcz was added to CYP90D1 (3.5 μM) at various final concentrations (a, 1; b, 2; c, 4; d, 8; e, 12; f, 20; g, 28 μM) (B). The spectral dissociation constant was calculated from a double reciprocal plot of absorbance differences, ΔA (436–417 nm) vs. the Pcz concentrations at 0.75 μM. The experiment was duplicated to establish reproducibility.