College of Food and Biological Engineering, Xiamen Key Laboratory of Marine Functional Food, Fujian Provincial Engineering Technology Research Center of Marine Functional Food, Fujian Collaborative Innovation Center for Exploitation and Utilization of Marine Biological Resources , Jimei University , Xiamen , Fujian 361021 , China.
Women and Children's Hospital Affiliated to Xiamen University , Xiamen , Fujian 361003 , China.
J Agric Food Chem. 2019 Nov 20;67(46):12918-12926. doi: 10.1021/acs.jafc.9b05279. Epub 2019 Nov 11.
The triosephosphate isomerase (TIM), Scy p 8, is a crab allergen and shows cross-reactivity in the shellfish. Here, recombinant Scy p 8 was expressed, and its crystal structure was determined at a resolution of 1.8 Å. The three-dimensional structure of Scy p 8 is primarily composed of a (β/α)-barrel motif prototype. Additionally, Scy p 8 showed cross-reactivity with high sequential and secondary structural identity among TIMs from shellfish species. The site-directed mutagenesis of critical amino acids of conformational epitopes was carried out, and the mutants of Trp 168 and Lys 237 to Ala reduced immunoglobulin E (IgE)-binding activity by approximately 30%, compared with wild-type TIM in an inhibition ELISA; however, it still induced basophil activation despite the interpatient variability between patients. These results can help to provide an accurate template for the analysis of the IgE binding and establish meaningful relationships between structure and allergenicity.
磷酸丙糖异构酶（TIM）、Scy p 8 是一种蟹过敏原，在贝类中表现出交叉反应性。本研究表达了重组 Scy p 8，并解析了其晶体结构，分辨率为 1.8Å。Scy p 8 的三维结构主要由（β/α）-桶原型组成。此外，Scy p 8 与来自贝类物种的 TIM 具有高序列和二级结构同源性的交叉反应性。对构象表位的关键氨基酸进行了定点突变，与野生型 TIM 相比，色氨酸 168 和赖氨酸 237 突变为丙氨酸的突变体在抑制 ELISA 中使免疫球蛋白 E（IgE）结合活性降低了约 30%；然而，尽管在患者之间存在个体间变异性，但它仍然诱导了嗜碱性粒细胞的活化。这些结果可以为 IgE 结合的分析提供准确的模板，并建立结构与变应原性之间的有意义关系。
