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Responsiveness of the major birch allergen Bet v 1 scaffold to the gastric environment: Impact on structure and allergenic activity
Author(s) -
Sancho Ana I.,
Wangorsch Andrea,
Jensen Bettina M.,
Watson Andrew,
Alexeev Yuri,
Johnson Phil E.,
Mackie Alan R.,
Neubauer Angela,
Reese Gerald,
BallmerWeber Barbara,
HoffmannSommergruber Karin,
Skov Per S.,
Vieths Stefan,
Mills Elisabeth N. Clare
Publication year - 2011
Publication title -
molecular nutrition and food research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.495
H-Index - 131
eISSN - 1613-4133
pISSN - 1613-4125
DOI - 10.1002/mnfr.201100025
Subject(s) - chemistry , digestion (alchemy) , circular dichroism , allergen , biochemistry , biophysics , pepsin , ionic strength , vesicle , chromatography , enzyme , allergy , biology , aqueous solution , immunology , organic chemistry , membrane
Scope: Four Bet v 1 homologous food allergens from celeriac (rApi g 1), apple (rMal d 1), peach (rPru p 1) and hazelnut (rCor a 1), were used to probe the structural responsiveness of the Bet v 1 scaffold to gastric digestion conditions and its impact on allergenicity. Methods and results: Low pH induced conformational changes of all homologues, which was reduced at physiological ionic strength for all except rPru p 1 as observed by circular dichroism (CD)‐spectroscopy. The homologues were rapidly digested by pepsin, losing their IgE binding activity, although the kinetics and patterns of digestion varied subtly between homologues, rApi g 1 being the most stable. We have demonstrated for the first time that gastric phosphatidyl‐choline (PC) induced conformational changes in all homologues but only rMal d 1 penetrated the PC vesicles as detected by fluorescence polarization, slowing its digestion and retaining more of its allergenic activity. PC enhanced basophil activation of all digested allergens except rApi g 1. Conclusion: The Bet v 1 scaffold is generally susceptible to low pH and pepsinolysis and interacts with PC vesicles, properties which can explain effects of the gastric environment on their allergenicity. These data show the importance of including surfactants in model digestion systems.