Barley ¦Ã3-hordein: Glycosylation at an atypical site, disulfide bridge analysis, and reactivity with IgE from patients allergic to wheat

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• 作者：Jacques Sné ; garoff^a ; Isabelle Bouchez^a ; ^{Isabelle.Bouchez@versailles.inra.fr} ; Mohamed El Amine Smaali^a ; Catherine Pecquet^b ; Nadia Raison-Peyron^c ; Pascale Jolivet^a ; Michel Lauriè ; re^d
• 关键词：CAM ; carbamidomethylated ; DIG ; digoxigenin ; IHHWP ; immediate hypersensitivity to hydrolyzed wheat protein ; LMW-GS ; low molecular weight glutenin subunit ; TFMS ; trifluoromethanesulfonic acid ; WDEIA ; wheat-dependent exercise-induced anaphylaxis
• 刊名：Biochimica et Biophysica Acta - Proteins and Proteomics
• 出版年：2013
• 出版时间：January, 2013
• 年：2013
• 卷：1834
• 期：1
• 页码：395-403
• 全文大小：696 K

文摘

Post translational modifications of a seed storage protein, barley ¦Ã3-hordein, were determined using immunochemical and mass spectrometry methods. IgE reactivity towards this protein was measured using sera from patients diagnosed with allergies to wheat. N-glycosylation was found at an atypical Asn-Leu-Cys site. The observed glycan contains xylose. This indicates that at least some ¦Ã3-hordein molecules trafficked through the Golgi apparatus. Disulfide bridges in native ¦Ã3-hordein were almost the same as those found in wheat ¦Ã46-gliadin, except the bridge involving the cysteine included in the glycosylation site. IgE reacted more strongly towards the recombinant than the natural ¦Ã3-hordein protein. IgE binding to ¦Ã3-hordein increased when the protein sample was reduced. Glycosylation and disulfide bridges therefore decrease epitope accessibility. Thus the IgE from patients sensitized to wheat cross-react with ¦Ã3-hordein due to sequence homology with wheat allergens rather than through shared carbohydrate determinants.