Homology modeling and characterization of IgE binding epitopes of mountain cedar allergen Jun a 3

Kizhake V. Soman, Terumi Midoro-Horiuti, Josephine C. Ferreon, Randall M. Goldblum, Edward G. Brooks, Alexander Kurosky, Werner Braun, Catherine H. Schein

Research output: Contribution to journalArticle

61 Scopus citations

Abstract

The Jun a 3 protein from mountain cedar (Juniperus ashei) pollen, a member of group 5 of the family of plant pathogenesis-related proteins (PR-proteins), reacts with serum IgE from patients with cedar hypersensitivity. We used the crystal structures of two other proteins of this group, thaumatin and an antifungal protein from tobacco, both ~50% identical in sequence to Jun a 3, as templates to build homology models for the allergen. The in-house programs EXDIS and FANTOM were used to extract distance and dihedral angle constraints from the Protein Data Bank files and determine energy-minimized structures. The mean backbone deviations for the energy-refined model structures from either of the templates is <1 Å, their conformational energies are low, and their stereochemical properties (determined with PROCHECK) are acceptable. The circular dichroism spectrum of Jun a 3 is consistent with the postulated β-sheet core. Tryptic fragments of Jun a 3 that reacted with IgE from allergic patients all mapped to one helical/loop surface of the models. The Jun a 3 models have features common to aerosol allergens from completely different protein families, suggesting that tertiary structural elements may mediate the triggering of an allergic response.

Original languageEnglish (US)
Pages (from-to)1601-1609
Number of pages9
JournalBiophysical journal
Volume79
Issue number3
DOIs
StatePublished - Jan 1 2000

ASJC Scopus subject areas

  • Biophysics

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