甲壳类动物4种过敏原的序列分析、抗原表位预测及三维结构建模

Sequence analysis,antigen epitopes prediction,and three dimensional structure modeling of four allergens in crustaceans

目的探明甲壳类动物各种过敏原之间是否存在相似性,以期深入研究甲壳类食品过敏原的构效关系。方法应用生物信息学方法,分析预测了甲壳类动物的4种过敏原—原肌球蛋白(TM)、精氨酸激酶(AK)、肌球蛋白轻链(MLC)和肌质钙结合蛋白(SCP)的二级结构、亲水性、可塑性、抗原性、表面可及性、线性抗原表位和三维结构等。结果 TM为超螺旋结构,而AK、MLC和SCP均为复合蛋白,含有较多的Turn和Coil结构;TM、AK、MLC和SCP 4种过敏原的亲水性区域均在60%以上,可塑性区域约为50%,抗原性区域均在60%以上。TM、AK、MLC和SCP分别有11、10、4和4个线性抗原表位。TM、AK、MLC和SCP的三维结构建模结果与相应的二级结构预测结果一致,基本能够反映此4种过敏原的空间构象。结论通过生物信息学方法分析,同时获得了甲壳类动物4种过敏原TM、AK、MLC和SCP的分子特征、抗原表位及部分三维结构,可望为进一步采用实验方法研究其构效关系奠定理论基础。

It is reported that there are four allergens in muscle of crustaceans, tropomysin （TM）, arginine kinase （AK）, myosin light chain （MLC）, and sarcoplasmic calcium-binding protein （SCP）. In order to find the similarity among the four allergens and laid the foundations for further analyzing their characterizations, we predicted and constructed the secondary structures, hydrophilicity, flexibility, antigenicity, surface probability, antigen epitopes and three dimensional structures of the four allergens by bioinformatics software. The results showed that the structure of TM was super helix, but AK, MLC and SCP were composite proteins contained a-helix, B-folding and more Turn and Coil domains. The rates of hydrophilic peptides in the sequences of four allergens were all above 60%, the flexible peptides about 50%, and antigenic peptides above 60%. In addition, the predicted antigen epitopes of TM, AK, MLC and SCP were 11, 10, 4, and 4, respectively. The three dimensional structures of four allergens were constructed and the prediction results were coincident with the results of secondary structure prediction of them. Summarily, the molecular characteristics, antigen epitopes and three dimensional structures of four allergens in crustaceans were obtained in our study, and all of these could provide the theory basis to further analyze the structure-activity relationship of the four allergens by experimental methods in the future.