Structure and Zeatin Binding of the Peach Allergen Pru p 1

Peach (Prunus persica) is among the fruits most frequently reported to cause food allergies. Allergic reactions commonly result from previous sensitization to the birch pollen allergen Bet v 1, followed by immunological cross-reactivity of IgE antibodies to structurally related proteins in peach. In this study, we present the three-dimensional NMR solution structure of the cross-reactive peach allergen Pru p 1 (isoform Pru p 1.0101). This 17.5 kDa protein adopts the canonical Bet v 1 fold, composed of a seven-stranded β-sheet and three α-helices enclosing an internal cavity. In Pru p 1, the inner surface of the cavity contains an array of hydroxyl-bearing amino acids surrounded by a hydrophobic patch, constituting a docking site for amphiphilic molecules. NMR-guided docking of the cytokinin molecule zeatin to the internal cavity of Pru p 1 provides a structure-based rationale for the effect that zeatin binding has on the protein's RNase activity.