Assessing impacts of physical processing methods on pea and lentil allergenic proteins

The vast majority of legume crops contain proteins that are known allergens for susceptible individuals. These include proteins from the 7S globulin family, which can comprise up to 70% of seed storage protein. We are investigating the effects of physical processing methods on the structure and allergenicity of Pisum sativum L. (pea) and Lens culinaris Medicus (lentil) globulins. Previously, working with un-processed recombinantly produced proteins, we obtained crystal structures of 7S globulins including pea vicillin and convicilin, and lentil vicilin. All three structures maintain the expected fold, but highlight minor differences in structure and crystal packing of possible relevance to packing upon seed deposition. Furthermore, we have completed a mass spectroscopic analysis of the post-translation modifications (PTM) detectable on these same un-processed proteins, highlighting an array of phosphorylation events. Mapping on the obtained crystal structures highlights significant Ig epitope overlap between pea, lentil, peanut and soya bean and significant coverage of the entire seed storage protein, emphasizing the challenge in addressing food allergies. Next steps are ongoing, with samples of these recombinant allergenic proteins being subjected to physical processing methods, followed by a comparative re-evaluation of structural aspects, PTM coverage and allergenicity.