Mala s 12 is a major allergen in patients with atopic eczema and has sequence similarities to the GMC oxidoreductase family

Background:  Atopic eczema (AE) is a chronic inflammatory skin disorder, characterized by impaired skin barrier and itch. The yeast Malassezia belongs to the normal human skin microflora and can induce IgE- and T-cell-mediated allergic reactions in AE patients. Previously, we have identified several IgE-binding components in Malassezia sympodialis extract. Methods:  Here, we report cloning, production and characterization of a M. sympodialis 67-kDa allergen. Results:  The sequence of the 67-kDa protein, termed Mala s 12, showed sequence similarity to the glucose–methanol–choline (GMC) oxidoreductase enzyme superfamily and was expressed as a recombinant protein in Escherichia coli. The purified protein bound flavin adenine dinucleotide with 1:1 stoichiometry per monomer of protein. The protein-bound flavin showed an extinction coefficient at 451 nm of 11.3 mM−1cm−1. The recombinant 67-kDa protein did not show any enzymatic activity when tested as oxidase or dehydrogenase using choline, glucose, myo-inositol, methanol, ethanol, 1-pentanol, benzyl alcohol, 2-phenylethanol, cholesterol or lauryl alcohol as possible substrates. Recombinant Mala s 12 was recognized by serum IgE from 13 of 21 (62%) M. sympodialis-sensitized AE patients indicating that the 67-kDa component is a major allergen. Conclusions:  The data show that Mala s 12 has sequence similarity to the GMC oxidoreductase family and is a major allergen in AE patients.