Using Proteomic Strategies for Sequencing and Post-Translational Modifications Assignment of Antigen-5, a Major Allergen from the Venom of the Social Wasp Polybia paulista

Abstract

Antigen-5 is one of the major allergens identified in wasp venoms, and despite the fact that its biological function is still unknown, many studies have demonstrated its allergenicity. In this study, the biochemical and structural characterization of antigen-5 from the venom of the social wasp Polybia paulista are reported. A gel-based mass spectrometry strategy with CID fragmentation methods and classical protocols of protein chemistry, which included N- and C-terminal sequencing, were used to assign the complete sequence and determine the presence/location of the post-translational modifications (PTMs) of this protein. Six different isoforms of antigen-5 were identified in the crude venom of P. paulista ; the most abundant, which corresponds to the intact form of this protein, was recognized by the pool of human specific-IgE. This protein was extensively sequenced through CID mass spectrometry, and a series of PTMs were observed such as hydroxylation, phosphorylation, and glycosylation. Sequence data revealed that this protein has 59.3-93.7% identity with antigen-5 proteins from other known vespid venoms. The molecular model of P. paulista antigen-5 shows that this protein has three α-helices, one 310 helix, and four β-sheets covering 28 and 17.9% of the sequence, respectively. The identification and characterization of allergenic compounds is essential for the development of advanced component-resolved allergy diagnostics and treatment.

Allergens of <b><i>Blomia tropicalis</i></b>: An Overview of Recombinant Molecules

“…Moreover, cross-reactive carbohydrate determinants have been reported to induce carbohydrate-specific IgE antibodies [81,82,83]. Some studies have experimentally identified glycosylation sites in natural allergens as well as in recombinant allergens, highlighting their importance for IgE binding and for their recognition by innate immune cells [82,84,85,86]. For Blomia allergens, on the other hand, data on glycosylation have been mostly restricted to bioinformatics predictions [29,30,62,67,70,74].…”

Application of recombinant antigen 5 allergens from seven allergy-relevant Hymenoptera species in diagnostics

“…The antigens 5 are the most abundant proteins and most potent allergens in vespid venoms . These proteins of unknown function were found in the venoms of nearly all Vespoidea species, for example, social wasps of the Polistes, Dolichovespula, Vespa, Vespula and Polybia genera and show a varying degree of sequence homology.…”

IgE Reactivity of Recombinant Pac c 3 from the Asian Needle Ant <b><i>(Pachycondyla chinensis)</i></b>

“…However, we observed loss of recombinant protein during long periods of culture (>48 h), possibly due to degradation by yeast proteases [25]. Native antigen 5 is known to be modified posttranslationally, including hydroxylation, phosphorylation and glycosylation [26]. The effect of these modifications on IgE reactivity should be further investigated.…”