Boiling down the cysteine-stabilized LTP fold - loss of structural and immunological integrity of allergenic Art v 3 and Pru p 3 as a consequence of irreversible lanthionine formation.

•The crystal structure of Art v 3 revealed an alpha helical LTP fold with differently sized cavities.•Heat treatment in neutral buffer caused irreversible lanthionine induced structural changes.•Contrasting Art v 3, thermally denatured Pru p 3 retained partial antibody binding.•The buffer environment determines stability and epitope formation of LTPs during thermal treatment.