副猪嗜血杆菌神经氨酸酶的克隆测序与生物信息学分析

Cloning,sequecing,secondary structure and B-cell epitopes prediction of Haemophilus parasuis neuraminidase

对副猪嗜血杆菌神经氨酸酶基因进行PCR扩增、克隆和测序,并进行同源性比较。应用生物信息学方法,对副猪嗜血杆菌神经氨酸酶的二级结构和B细胞抗原表位进行预测。结果显示,副猪嗜血杆菌神经氨酸酶基因全长2 007bp,编码668个氨基酸,同源性分析显示所测5株不同血清型的副猪嗜血杆菌神经氨酸酶基因相似度在98%以上,对应氨基酸相似度在97%以上。二级结构的预测结果显示该酶主要以无规则卷曲、α螺旋和延伸链为主,只有少数的β转角;推测该酶有16个B细胞优势抗原表位区域、8个糖基化位点。该研究为进一步分析副猪嗜血杆菌免疫机理、表位疫苗设计等奠定理论基础。

The aims of this study was to clone and sequence the neuraminidase gene of Haemophilus parasuis ,and predict its secondary structure and B-cell epitopes,which provides a theoretical basis for the study of immune mechanism and subunit vaccine. The neuraminidase gene was amplified,cloned, sequenced and blasted. By using bioinformatics methods, the secondary structure and B-cell preponderant epitope of neuraminidase were predicted. The results showed that the neuraminidase gene is 2 007 bp,encoding 668 amino acids. The homology of the neuraminidase gene and encoding amino acids in 5 serotypic Haemophilus parasuis are up to 98% and 97% ,respectively. Using the SOPMA method, prediction of the secondary structure of the neuraminidase showed that random coils,a-helix and extended strand were the main structural type of the flexible region in secondary structure, and contain a small amount of β-turn. The neuraminidase was supposed contain 16 potential antigen epitopes and 8 potential glycosylated sites. These results provided a theoretical basis for the further study of immune mechanisms and epitope vaccine design.