框镜鲤维氏气单胞菌CY0806株气溶素基因的生物信息学分析及原核表达

Bioinformatic analysis and prokaryotic expression of Aerosysin gene of Aeromonas veronii isolated from Cyprinus carpio

为深入研究维氏气单胞菌(Aeromonas veronii)毒力因子气溶素(aerA),本实验从框镜鲤A.veroniiCY0806株中克隆aerA基因,进行同源性分析和构建系统进化树,并进行生物信息学分析、诱导表达和检测。结果表明aerA基因全长1 471 bp,编码490个氨基酸,CY0806株aerA与A.veronii EF620533.1株同源性为95%,与EF620533.1、AB109093.1和ET034117.1在同一分支;推测其相对分子质量约为54.33 ku,理论等电点为5.90,摩尔消光系数为138 810,半衰期为30 h(体外培养的哺乳动物网状细胞),不稳定性系数为31.87,脂肪系数为71.86,总平均疏水性为-0.445;aerA蛋白具有信号肽,不存在跨膜区,二级结构分析表明aerA蛋白结构比较复杂。本研究对aerA基因进行了原核表达,产物具有一定的免疫原性。研究结果为进一步研究A.veronii aerA的功能和诊断、防治奠定基础。

In this experiment,the aerA gene was amplaified from Aeromonas veronii CY0806 isolated from Cyprinus carpio by PCR,and expressed in BL21（DE3）.The results showed that the length of aerA gene was 1 471 bp coding 490 amino acid residues,.The aerA gene of CY0806 was 95% in homology with A.veronii（EF620533.1） and was clustered into the same branch with A.veronii（EF620533.1,AB109093.1 and A.veronii）.The molecular weight,theoretical pI,Ext.coefficient,half-life,instability index,aliphatic index and grand average of hydropathicity were 54.33 ku,5.90,138810,30 hours（mammalian reticulocytes,in vitro）,31.87,71.86 and-0.445,respectively.The aerA contains signal peptide but no transmembrane region.The results of secondry structural analysis showed the structure of aerA was complex.The expressed product was in line with expectations about molecular weight and had immunogenicity.