The allergen Mus m 1.0102: Dissecting the relationship between molecular conformation and allergenic potency

Elena Ferrari, Emanuela Casali, Samuele E. Burastero, Alberto Spisni, Thelma A. Pertinhez

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Abstract

Background The species Mus musculus experiences an obligate proteinuria: predominant are the Major Urinary Proteins (MUPs), that, collectively known as the major mouse allergen Mus m 1, are among the most important aeroallergens for mouse allergic patients. The production of a soluble and stable hypoallergenic form of Mus m 1 is essential for the development of immunotherapeutic protocols to treat allergic symptoms. Methods We introduced the substitution C138S in recombinant Mus m 1.0102, an allergenic isoform of Mus m 1. Solubility, conformation, stability and ability to refold after chemical denaturation were investigated with dynamic light scattering, circular dichroism, fluorescence and NMR spectroscopy. An in vitro degranulation assay was used to evaluate the protein allergenic potential, and compare it with Mus m 1.0102 and with an hypoallergenic variant bearing the substitution Y120A. Results Mus m 1.0102-C138S retains a native-like fold revealing, however, local conformational alterations that influence some of its physical and allergenic properties: it is monodispersed, thermostable up to 56 °C, able to reversibly unfold and it exhibits an enhanced allergenicity. Conclusions The unique free thiol group affects the solution structural stability of the native protein. Because the mutant C138S does not aggregate over time it is a good lead protein to develop diagnostic and therapeutic applications. General significance We elucidated the relationship between unfolding reversibility and sulphydryl reactivity. We ascribed the enhanced allergenicity of the mutant C138S to an increased accessibility of its allergenic determinants, an enticing feature to further investigate the structural elements of the allergen-IgE interface.

Original languageEnglish
Pages (from-to)1548-1557
Number of pages10
JournalBiochimica et Biophysica Acta - Proteins and Proteomics
Volume1864
Issue number11
DOIs
Publication statusPublished - Nov 1 2016

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Keywords

  • Conserved free cysteine
  • Lipocalin fold stability
  • Mus m 1 allergen
  • Protein aggregation
  • Thiol/disulfide exchange
  • Unfolding reversibility

ASJC Scopus subject areas

  • Analytical Chemistry
  • Biophysics
  • Biochemistry
  • Molecular Biology

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