scholarly journals Structure and IgE cross-reactivity among walnut and peanut vicilin leader sequences

2021 ◽  
Author(s):  
Jacqueline Nesbit ◽  
Alexander Foo ◽  
Stephen Gipson ◽  
Pierre Bushel ◽  
Eugene DeRose ◽  
...  
Keyword(s):  
Disulfide Bonds ◽  
Storage Proteins ◽  
Seed Storage ◽  
Seed Storage Proteins ◽  
Cross Reactivity ◽  
Peptide Microarrays ◽  
Sequence Identity ◽  
Amino Acid Properties ◽  
Ara H 1 ◽  
Glass Slides

Background: Vicilin seed storage proteins are translated with N-terminal leader sequences (LSs) that are cleaved to yield the mature protein. These LSs were thought to be unstructured and rapidly degraded. However, Ara h 1 and Jug r 2 LS (A1LS, J2LS) have been identified in seeds, and immunodominant IgE epitopes detected. Here, common sequences containing structured CxxxC-repeat motifs were identified as potential mediators of IgE cross-reactivity despite very low (17%) sequence identity. Method: Linear IgE epitopes were identified by peptide microarrays, in which overlapping 15-mer peptides on glass slides, were incubated with sera from peanut, walnut or dual allergic individuals. Similar epitopes were computationally predicted. Peanut A1LS and walnut J2LS fragments (J2.1, J2.2, J2.3) each with a CxxxC vicilin LS motif were identified, cloned, expressed, purified and their structures solved using solution-NMR to locate and assess epitopes on the structure. Results: A1LS and J2LSs reveal similar helix-turn-helix motifs connected by disulfide bonds between adjacent CxxxC repeats forming α-hairpin structures. Peanut-allergic IgE bound more frequently to the J2LSs, regardless of walnut allergic status or A1LS binding. IgE binding pattern to peptides from both J2LS and A1LS, along with structure and computational predictions, suggest that the structure and conserved amino acid properties of peptides determine cross-reactivity. The properties of LS IgE epitopes were closely related to epitopes in 2S albumins. Conclusion: The shared α-hairpin structure is a stable scaffold that contributes to cross-reactivity despite low sequence identity. Biophysical properties are a better predictor of distant cross-reactivity than traditional measures of evolutionary conservation.

scholarly journals Food allergy: nuts and tree nuts

2006 ◽  
Vol 96 (S2) ◽  
pp. S95-S102 ◽  
Author(s):  
Jesus F. Crespo ◽  
John M. James ◽  
Consuelo Fernandez-Rodriguez ◽  
Julia Rodriguez
Keyword(s):  
Food Allergy ◽  
Dietary Habits ◽  
Storage Proteins ◽  
Seed Storage ◽  
Seed Storage Proteins ◽  
Cross Reactivity ◽  
Severe Reaction ◽  
Immunological Mechanism ◽  
Pathogenesis Related Protein ◽  
The Usa

Nuts are a well-defined cause of food allergy, which affect approximately 1 % of the general population in the UK and the USA. There do appear to be differences in the frequency of nut allergy between different countries because of different dietary habits and cooking procedures. For example, in the USA and France, peanuts are one of the most frequent causes of food allergy, but in other countries, it seems to be less common. Genetic factors, in particular, appear to play a role in the development of peanut allergy. While the majority of nut allergens are seed storage proteins, other nut allergens are profilins and pathogenesis-related protein homologues, considered as panallergens because of their widespread distribution in plants. The presence of specific IgE antibodies to several nuts is a common clinical finding, but the clinical relevance of this cross-reactivity is usually limited. Allergic reactions to nuts appear to be particularly severe, sometimes even life-threatening, and fatal reactions following their ingestion have been documented. Food allergy is diagnosed by identifying an underlying immunological mechanism (i.e. allergic testing), and establishing a causal relationship between food ingestion and symptoms (i.e. oral challenges). In natural history investigations carried out in peanut-allergic children, approximately 20 % of the cases outgrew their allergy or developed oral tolerance. The treatment of nut allergies should include patient and family education about avoiding all presentations of the food and the potential for a severe reaction caused by accidental ingestion. Patients and families should be instructed how to recognise early symptoms of an allergic reaction and how to treat severe anaphylaxis promptly.

scholarly journals Seed Storage Proteins, 2S Albumin And 11S Globulin, Associated to Severe Allergic Reactions after Flaxseed Intake

2021 ◽  
Vol 32 (5) ◽  
Author(s):  
C Bueno-Díaz ◽  
C Biserni ◽  
L Martín-Pedraza ◽  
M de las Heras ◽  
C Blanco ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Storage Proteins ◽  
Binding Capacity ◽  
Seed Storage ◽  
Seed Storage Proteins ◽  
Cross Reactivity ◽  
2S Albumin ◽  
11S Globulin ◽  
Flaxseed Extract

Background: Given the increased popularity of flaxseed in meals, several cases of allergy to these seeds have been reported. Little is known about allergens implicated in hypersensitivity reactions to these seeds. The present work aimed to identify the allergens involved in IgE-mediated reactions in five patients with a clinical history of severe systemic symptoms after flaxseed consumption. Methods: Proteins susceptible to be allergens with IgE-binding capacity were purified from flaxseed extract by chromatographic techniques. Their identification was achieved via MALDI-TOF mass spectrometry. Immunoassays were performed using the five allergic patient’s era either by testing them individually or as a pool. Results: Four out of five patients recognized a low-molecular-mass protein (around 13kDa) by immunoblotting of the flaxseed extract, while two patients recognized a protein of approximately 55 kDa. They were identified by mass spectrometry as flaxseed 2S albumin, included into WHO/IUIS allergen nomenclature as Lin u 1,and 11S globulin, respectively. Inhibition assays revealed in vitro IgE-cross-reactivity of Lin u 1 with peanut and cashew nut proteins, while IgE recognition of 11S globulin by patients’ sera was partially inhibited by several plant-derived sources. Conclusions: Seed storage proteins from flaxseed were involved in the development of severe symptoms in five individuals and exhibited cross-reactivity with other allergenic sources. Besides the severity of flaxseed allergy in patients sensitized to 2S albumin, it is the first time that the 11S globulin is identified as a potential allergen. We consider that these data should be taken into account for a more accurate diagnosis of patients.

scholarly journals Wheat (Triticum aestivum L.) TaHMW1D Transcript Variants Are Highly Expressed in Response to Heat Stress and in Grains Located in Distal Part of the Spike

Plants ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 687
Author(s):  
Chan Seop Ko ◽  
Jin-Baek Kim ◽  
Min Jeong Hong ◽  
Yong Weon Seo
Keyword(s):  
Heat Stress ◽  
High Temperature ◽  
Temperature Stress ◽  
Storage Proteins ◽  
Seed Storage ◽  
Seed Storage Proteins ◽  
Grain Filling ◽  
High Temperature Stress ◽  
Two Dimensional Gel Electrophoresis ◽  
Transcript Variants

High-temperature stress during the grain filling stage has a deleterious effect on grain yield and end-use quality. Plants undergo various transcriptional events of protein complexity as defensive responses to various stressors. The “Keumgang” wheat cultivar was subjected to high-temperature stress for 6 and 10 days beginning 9 days after anthesis, then two-dimensional gel electrophoresis (2DE) and peptide analyses were performed. Spots showing decreased contents in stressed plants were shown to have strong similarities with a high-molecular glutenin gene, TraesCS1D02G317301 (TaHMW1D). QRT-PCR results confirmed that TaHMW1D was expressed in its full form and in the form of four different transcript variants. These events always occurred between repetitive regions at specific deletion sites (5′-CAA (Glutamine) GG/TG (Glycine) or (Valine)-3′, 5′-GGG (Glycine) CAA (Glutamine) -3′) in an exonic region. Heat stress led to a significant increase in the expression of the transcript variants. This was most evident in the distal parts of the spike. Considering the importance of high-molecular weight glutenin subunits of seed storage proteins, stressed plants might choose shorter polypeptides while retaining glutenin function, thus maintaining the expression of glutenin motifs and conserved sites.

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