Identification of continuous, allergenic regions of the major shrimp allergen Pen a 1 (tropomyosin)
Identification of continuous, allergenic regions of the major shrimp allergen Pen a 1 (tropomyosin)
复制标题
DOI：
10.1159/000048166
复制
发表时间：
2002-01-01
影响因子：
2.8
通讯作者：
Reese, G
中科院分区：
文献类型：
--
作者：
Ayuso, R;Lehrer, SB;Reese, G
背景：甲壳类和软体动物是过敏反应的常见原因。在虾中鉴定的唯一主要过敏原是肌肉蛋白原肌球蛋白;至少80%的虾过敏受试者对原肌球蛋白有反应。此外，原肌球蛋白是其他甲壳类动物（如龙虾、螃蟹和软体动物）以及其他节肢动物（如屋尘螨和蟑螂）的重要过敏原，并被认为是无脊椎动物临床交叉敏感性的原因。相反，脊椎动物原肌球蛋白被认为是非过敏性的。目的：蛋白质致敏性的基础尚未解决。因此，原肌球蛋白分子提供了一个很好的机会，研究蛋白质结构和变应原性之间的关系。本研究的目的是确定的IgE结合区域的笔1和比较这些区域与其他过敏性和非过敏原肌球蛋白的同源序列。研究方法：合成了跨越整个Pen a 1分子的46个重叠肽（长度：15个氨基酸;偏移：6个氨基酸），并测试了与来自18个虾过敏受试者的血清的IgE抗体反应性，以鉴定虾原肌球蛋白的IgE结合区域。结果：根据IgE反应性的频率和强度，确定了五个主要的IgE结合区域。所有五个主要IgE结合区的长度为15-38个氨基酸。鉴定的主要IgE结合区域为：区域1：Pen a 1（43-57）;区域2：Pen a 1（85-105）;区域3：Pen a 1（133 - 148）;区域4：Pen a 1（187-202）和区域5：Pen a 1（247-284）。此外，22种肽被归类为次要IgE结合区，12种肽不结合任何IgE抗体。与整个分子相比，在五个IgE结合区域中的氨基酸组组成中未检测到实质性差异。Pen a 1 IgE结合区与致敏节肢动物原肌球蛋白同源区的序列同一性和相似性高达100%，而与同源脊椎动物序列的同一性和相似性分别为36 ~ 76%和53 ~ 85%。结论：五个主要的IgE结合区的过敏性虾原肌球蛋白，笔1，被确定为位于约42个氨基酸（7 heptads）的定期间隔，这表明与重复卷曲螺旋结构的原肌球蛋白分子的关系。Pen a 1 IgE结合区与无脊椎动物原肌球蛋白同源序列之间的高度相似性以及与脊椎动物原肌球蛋白同源区的较低相似性百分比支持变应原性原肌球蛋白交叉反应性的结构基础。版权所有（C）2002 S. Karger AG，巴塞尔。
Background: Crustaceans and mollusks are a frequent cause of allergic reactions. The only major allergen identified in shrimp is the muscle protein tropomyosin; at least 80% of shrimp-allergic subjects react to tropomyosin. Furthermore, tropomyosin is an important allergen in other crustaceans such as lobsters, crabs and mollusks, as well as other arthropods such as house dust mites and cockroaches, and has been implied as the cause of clinical cross-sensitivity among invertebrates. In contrast, vertebrate tropomyosins are considered nonallergenic. Objective: The basis of the allergenicity of proteins has not yet been resolved. Thus, tropomyosin molecules provide an excellent opportunity to study the relationship between protein structure and allergenicity. The aim of the current study was to identify the IgE-binding regions of Pen a 1 and compare these regions with homologous sequences in other allergenic and nonallergenic tropomyosins. Methods: Forty-six overlapping peptides (length: 15 amino acids; offset: 6 amino acids) spanning the entire Pen a 1 molecule were synthesized and tested for IgE antibody reactivity with sera from 18 shrimp-allergic subjects to identify the IgE-binding regions of shrimp tropomyosin. Results: Based on the frequency and intensity of the IgE reactivities, five major IgE-binding regions were identified. All five major IgE-binding regions were 15-38 amino acids long. The major IgE-binding regions identified were: region 1: Pen a 1 (43-57); region 2: Pen a 1 (85-105); region 3: Pen a 1 (133148); region 4: Pen a 1 (187-202), and region 5: Pen a 1 (247-284). In addition, 22 peptides were categorized as minor IgE-binding regions, and 12 peptides did not bind any IgE antibodies. No substantial differences in amino acid group composition in the five IgE-binding regions compared to the whole molecule were detected. Sequence identities and similarities of the Pen a 1 IgE-binding regions with homologous regions of allergenic arthropod tropomyosins were as high as 100%, whereas identities and similarities with homologous vertebrate sequences ranged from 36 to 76% and 53 to 85%, respectively. Conclusion: Five major IgE-binding regions of the allergenic shrimp tropomyosin, Pen a 1, were identified which are positioned at regular intervals of approximately 42 amino acids (7 heptads), suggesting a relationship with the repetitive coiled-coil structure of the tropomyosin molecule. The high degree of similarity between Pen a 1 IgE-binding regions and homologous sequences in invertebrate tropomyosins and the lower percentage of similarity with homologous regions of vertebrate tropomyosins supports a structural basis for cross-reactivity of allergenic tropomyosins. Copyright (C) 2002 S. Karger AG, Basel.