FIGURE 2.
Fra a proteins bind natural flavonoids. ITC representative experiments demonstrating binding of different flavonoids to Fra a 1E (a), Fra a 2 (b), and Fra a 3 (c) are shown. Concentrated solutions of quercetin-3-O-glucuronide, myricetin, and (+)-catechin (as indicated) were injected into the ITC cell containing the respective protein solutions. The values of the dissociation constants (Kd) are indicated (averaged values over several independent experiments with S.D. between brackets). The thermograms for the Fra a 3 (+) catechin pair (c) indicate the presence of two distinct ligand binding sites with high (Kd1) and low high (Kd2) affinities, respectively.