Linear IgE-epitope mapping and comparative structural homology modeling of hazelnut and English walnut 11S globulins

Jason M. Robotham, Gregg G. Hoffman, Suzanne S Teuber, Kirsten Beyer, Hugh A. Sampson, Shridhar K. Sathe, Kenneth H. Roux

Research output: Contribution to journalArticle

37 Scopus citations

Abstract

Allergic reactions to walnuts and hazelnuts can be serious. The 11S globulins (legumins) have been identified as important allergens in these and other nuts and seeds. Here we identify the linear IgE-binding epitopes of walnut and hazelnut 11S globulins, and generate 3D 11S globulin models to map the locations of the epitopes for comparison to other allergenic homologues. Linear IgE-epitope mapping was performed by solid-phase overlapping 15-amino acid peptides probed with IgE from pooled allergic human sera. Several walnut (Jug r 4) and hazelnut (Cor a 9) 11S globulin peptides with reactivity to patient IgE were identified. Comparative alignment with cashew (Ana o 2), peanut (Ara h 3), and soybean G1 (Gly m 6.0101) and G2 (Gly m 6.0201) allergenic homologues revealed several shared allergenic 'hot spots'. Homology modeling was performed based on the atomic structure of the soybean glycinin. Surface map comparisons between the tree nut and peanut homologues revealed structural motifs that could be important for IgE elicitation and binding and show that, contrary to predictions, the reactive epitopes are widely distributed throughout the monomeric subunits, both internally and externally, including regions occluded by quaternary subunit association. These findings reveal structural features that may be important to allergenicity and cross-reactivity of this protein class.

Original languageEnglish (US)
Pages (from-to)2975-2984
Number of pages10
JournalMolecular Immunology
Volume46
Issue number15
DOIs
StatePublished - Sep 2009

Keywords

  • 11S globulin
  • Cor a 9
  • Epitope mapping
  • Food allergy
  • Hazelnut allergen
  • Homology modeling
  • Jug r 4
  • Legumin
  • Tree nut allergy
  • Walnut allergen

ASJC Scopus subject areas

  • Molecular Biology
  • Immunology

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