Conformational Flexibility of a Lipocalin Allergen (Mus m 1): Implications for Molecular Allergy Diagnostics

Mus m 1 lipocalin is the cause of mouse allergy in sensitized individuals. The production of a soluble, stable, and immunogenic isoform of Mus m 1 is essential for developing new diagnostic tools and immunotherapeutic protocols for treating allergic symptoms. To that end, using molecular dynamics (MD), we explored the impact of substitutions at positions 120 and 138 on the structure and dynamics of the allergic isoform Mus m 1.0102. HINT-based analysis of the MD trajectories, obtained for the mutants Y120F, Y120A, C138S, and C138A, allowed the assessment of the mutations' impact on the network of intramolecular interactions, providing insights into the mechanisms underlying protein stability, dynamics, and allergenic reactivity. The C138A mutant revealed a reduction in the solvent-accessible surface area in the region of the mutated residue, of the radius of gyration, and of the alpha-helix displacement from the beta-barrel, features that correlate with an increase in folding stability and a satisfactory allergenic potential. We consider C138A a good candidate to be exploited for diagnostic and vaccine purposes.