Background: Der p 5 is an important allergen of Dermatophagoides pteronyssinus that
plays a key role in allergic airway diseases. Its three dimensional structure (PDB 3MQ1) consists of
three anti-parallel α-helices arranged in a helical bundle. Aggregation of Der p5 can modulate its
allergenicity. This study aimed to identify the key residues of IgE binding epitopes of Der p 5.
Methods: IgE binding epitopes of Der p 5 were characterized as follow. An in silico prediction of
the epitope was performed with the help of SEPPA program. We also made a mapping of the epitope
by using an overlapping library of peptides that encompass the sequence of mature Der p 5.
Finally, an alanine scanning mutagenesis allowed us to define the key residues of the allergen involved
in its interaction with IgE. The integrity of the structure of the different protein's mutants
was assessed by far UV circular dichroism.
Results: The presented data indicate that the major epitope sequence of Der p 5 is
90DRLMQRKDLDIFEQYNLEM108. Residues L98, D99, I100, F101, E102 and Y104 appear to be
important for IgE binding.
Conclusion: This study highlighted the residues of Der p 5 essential for IgE binding. The identification
of the major residues epitope of Der p 5 allergen may participate in the selection and engineering
of new hypoallergens used in immunotherapy.