Pathogenesis related proteins: A defensin for plants but an allergen for humans

Pathogenesis related (PR) proteins are defensins expressed upon biotic and abiotic stress by plants. They are also synthesized in specific plant parts such as root, stem, leaves, pollen grains and fruits. According to the current classification, there are 19 different classes of PR-Proteins, 8 out of 19 are proven to exhibit allergic reactions in human. Here, we carried out the allergenicity potential test for the remaining 11 classes of PR-Proteins using in-silico approaches. Our analysis suggests that the other 11 families also have the allergenic potential. We modelled the proteins for which our predictions suggested them to be allergens and for which the crystal structures were not available. We then predicted the B-cell epitope binding regions for all the proteins and used molecular docking approach to study the allergen-antibody interaction. Our findings suggest that all the selected proteins (belonging to 11 families of PR) analysed, can potentially be classified as allergens. We also provide evidence that the number of IgE binding-residues in the allergens is correlated with their respective binding energies with the IgE molecule. This study will be highly relevant to understand the allergenic potential of PR-Proteins to make an informed decision about the consumption of food with high degree of PR-expression.