Protein structure plays a critical role in peanut allergen stability and may determine immunodominant IgE-binding epitopes
Protein structure plays a critical role in peanut allergen stability and may determine immunodominant IgE-binding epitopes
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DOI：
10.4049/jimmunol.169.2.882
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发表时间：
2002-07-15
影响因子：
4.4
通讯作者：
Bannon, GA
中科院分区：
文献类型：
--
作者：
Sen, M;Kopper, R;Bannon, GA
对花生的超敏反应是由IgE抗体介导的对几种花生蛋白过敏原的反应。在这些过敏原蛋白中，Ara h 2是最常见的过敏原之一. Ara h 2是一种分子量为17 kDa的蛋白质，有8个半胱氨酸残基，可以形成多达4个二硫键。圆二色性研究表明，与天然蛋白质相比，在二级和三级结构的减少阿糖胞苷h 2的实质性变化。在用胰蛋白酶、胰凝乳蛋白酶或胃蛋白酶处理后，产生许多相对较大的片段，其对进一步的酶消化具有抗性。这些抗性Ara h 2肽片段含有完整的IgE结合表位和几个潜在的酶切位点，这些酶切位点被蛋白质的紧凑结构保护免受酶的影响。尽管蛋白酶的作用，酶处理的过敏原基本上保持完整，直到当二硫键被还原时片段解离。氨基酸序列分析表明，它们含有大部分的免疫显性IgE结合表位的抗性蛋白片段。这些结果提供了过敏原结构和免疫显性IgE结合表位之间的联系，在一个人口的食物过敏的个人。
Hypersensitivity to peanuts is a reaction mediated by IgE Abs in response to several peanut protein allergens. Among these allergenic proteins, Ara h 2 is one of the most commonly recognized allergens. Ara h 2 is a 17-kDa protein that has eight cysteine residues that could form up to four disulfide bonds. Circular dichroism studies showed substantial changes in the secondary and tertiary structures of the reduced Ara h 2 as compared with the native protein. Upon treatment with trypsin, chymotrypsin, or pepsin, a number of relatively large fragments are produced that are resistant to further enzymatic digestion. These resistant Ara h 2 peptide fragments contain intact IgE-binding epitopes and several potential enzyme cut sites that are protected from the enzymes by the compact structure of the protein. The enzyme-treated allergen remains essentially intact despite the action of proteases until the fragments are dissociated when the disulfide linkages are reduced. Amino acid sequence analysis of the resistant protein fragments indicates that they contain most of the immunodominant IgE-binding eptiopes. These results provide a link between allergen structure and the immunodominant IgE-binding epitopes within a population of food-allergic individuals.