title: Structure, stability, and IgE binding of the peach allergen Peamaclein (Pru p 7).
abstract: Knowledge of the structural properties of allergenic proteins is a necessary prerequisite to better understand the molecular bases of their action, and also to design targeted structural/functional modifications. Peamaclein is a recently identified 7 kDa peach allergen that has been associated with severe allergic reactions in sensitive subjects. This protein represents the first component of a new allergen family, which has no 3D structure available yet. Here, we report the first experimental data on the 3D-structure of Peamaclein. Almost 75% of the backbone resonances, including two helical stretches in the N-terminal region, and four out of six cysteine pairs have been assigned by 2D-NMR using a natural protein sample. Simulated gastrointestinal digestion experiments have highlighted that Peamaclein is even more resistant to digestion than the peach major allergen Pru p 3. Only the heat-denatured protein becomes sensitive to intestinal proteases. Similar to Pru p 3, Peamaclein keeps its native 3D-structure up to 90°C, but it becomes unfolded at temperatures of 100-120°C. Heat denaturation affects the immunological properties of both peach allergens, which lose at least partially their IgE-binding epitopes. In conclusion, the data collected in this study provide a first set of information on the molecular properties of Peamaclein. Future studies could lead to the possible use of the denatured form of this protein as a vaccine, and of the inclusion of cooked peach in the diet of subjects allergic to Peamaclein.
authors.affiliation: Institute of Biosciences and BioResources, CNR, Via Pietro Castellino 111, Naples, I-80131, Italy.
authors.forename: Lisa
authors.initials: L
authors.lastname: Tuppo
authors.forename: Roberta
authors.initials: R
authors.lastname: Spadaccini
authors.forename: Claudia
authors.initials: C
authors.lastname: Alessandri
authors.forename: Hans
authors.initials: H
authors.lastname: Wienk
authors.forename: Rolf
authors.initials: R
authors.lastname: Boelens
authors.forename: Ivana
authors.initials: I
authors.lastname: Giangrieco
authors.forename: Maurizio
authors.initials: M
authors.lastname: Tamburrini
authors.forename: Adriano
authors.initials: A
authors.lastname: Mari
authors.forename: Delia
authors.initials: D
authors.lastname: Picone
authors.forename: Maria Antonietta
authors.initials: MA
authors.lastname: Ciardiello
mesh_terms: D000485:Allergens / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*; D000595:Amino Acid Sequence; D052179:Antigens, Plant / Q000276:immunology; D002851:Chromatography, High Pressure Liquid; D002942:Circular Dichroism; D005753:Gastric Mucosa / Q000378:metabolism; D006358:Hot Temperature; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*; D011485:Protein Binding; D055550:Protein Stability; D012996:Solutions
chemical_list: D000485:Allergens; D052179:Antigens, Plant; D010940:Plant Proteins; C463181:Pru p 3 allergen; D012996:Solutions; C582428:peamaclein protein, Prunus persica; D007073:Immunoglobulin E
keywords: IgE binding; NMR; Peamaclein; Pru p 7; allergen; heat stability; simulated gastrointestinal digestion