Identification of triosephosphate isomerase as a novel allergen in Octopus fangsiao
Identification of triosephosphate isomerase as a novel allergen in Octopus fangsiao
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DOI：
10.1016/j.molimm.2017.02.004
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发表时间：
2017-05-01
影响因子：
3.6
通讯作者：
Liu, Guang-Ming
中科院分区：
文献类型：
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作者：
Yang, Yang;Chen, Zhong-Wei;Liu, Guang-Ming
章鱼因其营养价值是人类饮食中重要的软体动物，但它也会引起人类的过敏反应。来自章鱼的主要过敏原已经确定，而新的过敏原的知识仍然很差。本研究从章鱼（octopus fangsiao）中纯化了一种分子量为28 kDa的新变应原蛋白，并通过质谱分析鉴定为三磷酸异构酶（TIM）。TIM在45℃以上聚集，在极端pH条件下，由于二级结构的改变，其ige结合活性受到影响。在模拟胃液消化中，TIM可以被降解成小片段，同时保留80%以上的ige结合活性。克隆了O. fangsiao TIM全长cDNA (1140 bp)，编码247个氨基酸残基，并在大肠杆菌BL21中成功表达了完整的重组TIM，其免疫反应性与原TIM相似。近缘种TIM的交叉反应强度不同，揭示了其表位的复杂性。生物信息学分析预测了TIM的8个线性表位。通过噬菌体展示技术，确定了一个构象表位(a (71)G(74)S(69)D(75)T(73)F（72)V(67)）。结果揭示了TIM的理化和免疫学特性，对低敏食物的开发和过敏诊断具有重要意义。(C) 2017 Elsevier Ltd.版权所有。
Octopus is an important mollusk in human dietary for its nutritional value, however it also causes allergic reactions in humans. Major allergens from octopus have been identified, while the knowledge of novel allergens remains poor. In the present study, a novel allergen with molecular weight of 28 kDa protein was purified from octopus (Octopus fangsiao) and identified as triosephosphate isomerase (TIM) by mass spectrometry. TIM aggregated beyond 45 degrees C, and its IgE-binding activity was affected under extreme pH conditions due to the altered secondary structure. In simulated gastric fluid digestion, TIM can be degraded into small fragments, while retaining over 80% of the IgE-binding activity. The full-length cDNA of O. fangsiao TIM (1140 bp) was cloned, which encodes 247 amino acid residues, and the entire recombinant TIM was successfully expressed in Escherichia coli BL21, which showed similar immunoreactivity to the native TIM. Different intensity of cross-reactivity among TIM from related species revealed the complexity of its epitopes. Eight linear epitopes of TIM were predicted following bioinformatic analysis. Furthermore, a conformational epitope (A(71)G(74)S(69)D(75)T(73)F(72)V(67)) was confirmed by the phage display technology. The results revealed the physicochemical and immunological characteristics of TIM, which is significant in the development of hyposensitivity food and allergy diagnosis. (C) 2017 Elsevier Ltd. All rights reserved.