A single amino acid substitution on the surface of a natural hevein isoform (Hev b 6.0202), confers different IgE recognition

Abstract

Decreased immune reactivity of isoforms of major allergens has been reported. However, such claims have always been based on experiments with recombinant proteins. This work describes the molecular and physicochemical characterization of a hevein (Hev b 6.0201) natural isoform (Hev b 6.0202), which is present in rubber latex from Hevea brasiliensis. The isoallergen has a single substitution Asn14Asp, which gives rise to local differences in the surface potential, as observed from the crystal structure presented here. Besides, ELISA inhibition using serum pools of adult and pediatric patients showed reduced IgE-binding capacity ($27%) with the isoallergen. Overall, these results are relevant to delineate crucial residues involved in this dominant discontinuous epitope.

Sequence Polymorphisms of Major German Cockroach Allergens Bla g 1, Bla g 2, Bla g 4, and Bla g 5

“…Different batches of allergen extract could potentially have different isoforms, consequently influencing the characterization of allergen extracts using monoclonal antibodies. Sometimes, even a single amino acid substitution on the surface of allergens could confer different IgE or IgG recognition patterns [28]. …”

Highlights on Hevea brasiliensis (pro)hevein proteins

“…Anomalous staining and unexpected migration have often been reported, even using Tris-tricine gels with the "Schägger and von Jagow" protocol [43,61,64,[68][69][70]. Sharp bands may be difficult to observe and may require a large amount of proteins [46,64]. Hevein and its isoform may also be visualized on 20% native PAGE (pH 8.4; [46]).…”

“…Sharp bands may be difficult to observe and may require a large amount of proteins [46,64]. Hevein and its isoform may also be visualized on 20% native PAGE (pH 8.4; [46]). Hevein can be easily washed out from the M A N U S C R I P T A C C E P T E D ACCEPTED MANUSCRIPT gels, probably because of its small size and solubility in trichloroacetic acid (TCA) [16,71] ( Figure 3A).…”

“…It was proposed to call this variant pro-pseudohevein HEV1.3 [36]. Another hevein isoform, with a single mutation (Asn14Asp) is called Hev b 6.0202 [46].…”

“…During prohevein cleavage, a peptide of 4-6 residues linking hevein and the C-ter domain is lost (Ser-Gly-Glu-Gly-Val-Gly; residues [44][45][46][47][48][49] [37,38]. The physico-chemical characteristics of the proteins produced from hevein precursors are presented in Table 1.…”