副猪嗜血杆菌寡肽结合蛋白(OPPA)的序列分析及分子结构模拟

Sequence analysis and molecular structural simulation on oligopeptide binding protein A of Hps

通过研究副猪嗜血杆菌(Haemophilus parasuis,Hps)寡肽结合蛋白(Oligopeptide Binding Protein A,OppA)的生物学特性,为副猪嗜血杆菌亚单位疫苗的研制奠定基础。本试验设计了1对特异性引物,应用PCR方法来扩增副猪嗜血杆菌肽聚糖相关脂蛋白的全基因序列,并进行克隆和测序。并且采用生物信息学方法,对Hps的oppA基因核苷酸及其对应氨基酸序列进行比对,选取其中的血清学5型分离株,对其OppA蛋白的分子结构、理化性质及结构功能域、蛋白质二级结构等重要参数进行了预测和分析,并对OppA蛋白的三级结构进行了同源建模。PCR扩增出1 638bp的目的片段;测序结果显示出不同血清型Hps之间oppA基因核苷酸序列相似性有一定的差异,而所对应的氨基酸序列却差异更小;OppA蛋白的理论等电点为6.45,偏弱酸性;OppA蛋白的二级结构以α螺旋、不规则卷曲和β片层为主要构件;Hps的OppA蛋白的氨基酸序列与鼠疫耶尔森氏菌2Z23蛋白的同源性为57.20%,以2Z23蛋白结构为模板成功构建了Hps的OppA蛋白三维结构分子模型,该OppA蛋白三维结构中与2Z23蛋白相似,也有3个结构域,在疏水口袋中有1条5肽结构。Hps的OppA蛋白的成功模建为OppA蛋白功能的深入研究提供了参考依据。

In order to provide a theoretical basis for developing the subunit vaccine of Hps,the bionomics of oligopep- tide binding protein A（OppA） was lucubrated, The oppA complete gene was amplified by PCR with a pair of specific primers designed and synthesized,and was cloned and sequenced. The Hps OppA was analyzed and predicted by the tools of bioinformatics in the following aspects：the composition and alignment of nucleic acid sequences and amino acid sequences, molecular structure, physical and chemical characters, secondary and tertiary structure of protein and so on. The results revealed that 1638bp fragment of the oppA gene was amplified by PCR;there were less similarity in nucleic acid sequences than amino acid sequences among five Hps^the OppA（PI= 6.45） showed weak acidity;and main component of all secondary structures included ~ spiral , random coil and 13 sheet;The homology of the amino acid of Hps OppA and Y. pestis 2Z23 is 57.20%;The 3D models of Hps OppA were successfully constructed based on the template of 2Z23 of Like 2Z23,the teritiary structure of Hps OppA also contained 3 structural domain and a five peptide structure among the hydrophobic pocket. The homology modelling successfully of Hps OppA provides a refer to lucubrate the OppA.