Enhanced Pru p 3 IgE-binding activity by selective free fatty acid-interaction
Interaction between Pru p 3 and oleic acid.
Pawel Dubiela, Roberta Aina, Dominika Polak, Sabine Geiselhart, Piotr Humeniuk, Barbara Bohle, Stefano Alessandri, Rebecca Del Conte, Francesca Cantini, Tomasz Borowski, Merima Bublin, Karin Hoffmann-Sommergruber
Published online: July 13, 2017 in The Journal of Allergy and Clinical Immunology
Among plant food allergies the non-specific lipid transfer proteins (ns-LTPs) are regarded as inducers of severe up to life-threatening reactions. Although Pru p 3, the major food allergen from peach is considered as the primary sensitizer for nsLTP-caused allergies, little is known whether its biochemical function, that is binding a range of ligands has an impact on its allergenic activity, as measured by recognition of specific IgE antibodies.
The present study used nuclear magnetic resonance (NMR) to study the 3D structure of Pru p 3 and its interaction with a range of saturated and mono-/poly-unsaturated fatty acids. In parallel any change in IgE binding was investigated using sera from peach-allergic patients.
Our results showed that Pru p 3 preferentially binds in its cavity unsaturated free fatty acids, such as oleic acid, as shown by ANS assay and verified by NMR experiments. Furthermore, the interaction between oleic acid and Pru p 3 affects its 3D structure as indicated by molecular dynamic analysis. In detail, when interacting with a ligand the C-terminal loop is moved out towards the surface of the molecule changing accessibility of a known IgE epitope. As a consequence, this conformational change significantly increases IgE binding of Pru p 3 and thus its allergenicity.
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