High-resolution mass spectrometry unveils the molecular changes of ovalbumin induced by heating and their influence on IgE binding capacity

International audienceOvalbumin (OVA) is a food allergen whose allergenicity is modulated by heating. We aimed to establisha molecular connection between heat-induced modifications and the modulation of the IgE bindingcapacity of OVA. For this, we used model samples of heat-modified OVA with increasing complexity;glycated, aggregated or glycated and aggregated. Using sera from egg-allergic individuals, we showthat both aggregation and glycation strongly impacted IgE binding capacity, despite limited structuralchanges for glycated OVA. A molecular exploration at the amino acid level using high-resolution massspectrometry = revealed extensive cross-linking, mostly through disulfide and dehydroprotein bridges,and moderate but significant glycation. Structural modifications affected residues located within or ata few amino acids distance of known human linear IgE epitopes, such as C121, K123, S169, K190, K207,H332 and C368. We thus unveil key amino residues implicated in the changes in IgE binding of OVAinduced by heatin