外源性绵羊肺腺瘤病毒新疆株env囊膜蛋白生物信息学分析

Bioinformatic analysis of the env envelope protein of the Xinjiang strain of an exogenous ovine pulmonary adenomatosis virus

目的采用生物信息学方法分析外源性绵羊肺腺瘤病毒新疆株env囊膜蛋白的结构和功能。方法利用NCBI数据库查询外源性对绵羊肺腺瘤病毒新疆株env囊膜蛋白基因序列,采用在线软件ProtParam、Prot Scale、DNASTAR、SOPMA、SWISS MODEL、SOSUI、TMHMM2.0、Signal 4.1、Bepipred Linear Epitope Prediction、PROSITE SCAN、PSOTR分析预测env蛋白的理化性质、亲疏水性、二级结构、三级结构、跨膜区、信号肽、B细胞表位、结构域、亚细胞定位。结果 env蛋白由615个氨基酸组成,分子式为C_(3144)H_(4924)N_(840)O_(879)S_(29),相对分子质量为69.5×10^(3),理论等电点为8.48,不稳定系数为37.04(为稳定蛋白),脂肪系数平均为99.56,总平均亲水性为-0.048。二级结构以α-螺旋为主,占42.76%,无规卷曲占38.7%,延伸链占16.59%,β-转角占1.59%。三级结构env蛋白序列与同源模板的序列在408~540区域存在21%的同源性,只能进行部分同源建模。env蛋白存在2个跨膜区,无信号肽。env蛋白包含有20个线性表位,其中356-442、490-555、104-131、206-230、448-469区段是env蛋白的优势抗原表位区段。env蛋白包含9个N-糖基化位点,4个蛋白激酶C磷酸化作用位点,4个酪蛋白激酶Ⅱ磷酸化作用位点,4个N-豆蔻酰基化位点,1个酰胺化位点,1个细胞附着序列位点。亚细胞定位分析预测env蛋白为细胞膜蛋白,env蛋白绵羊肺腺瘤病毒的囊膜蛋白。结论外源性绵羊肺腺瘤病毒新疆株env囊膜蛋白存在多个B细胞抗原表位及1个细胞附着序列位点,可作为潜在抗原用于env蛋白绵羊肺腺瘤病毒感染疫苗的研制。

Objective To use bioinformatics to analyze the env envelope protein of the Xinjiang strain of an exogenous ovine pulmonary adenomatosis virus and to predict its immunogenicity and its function. Methods Online bioinformatic software, such as ProtParam, Prot Scale, DNASTAR, SOPMA, SWISS MODEL, SOSUI, TMHMM2.0, Signal 4.1, Bepipred Linear Epitope Prediction, PROSITE SCAN, and PSORT, were used to predict the physicochemical properties and hydrophilicity of the env protein, its secondary structure, its tertiary structure, its transmembrane regions, its signal peptides, its B-cell epitopes, and its subcellular localization. Results The env protein consists of 615 amino acids with the formula: C_(3144)H_(4924)N_(840)O_(879)S_(29), it has a molecular weight of 26.5×10^(3), a theoretical isoelectric point of 8.48, and an instability coefficient of 37.04. The env protein is a stable protein. Its average aliphatic index was 99.56, and its total average hydrophilicity was-0.048. The protein’s secondary structure mainly consists of α-helices(42.76%), random coils(38.7%), extended strands(16.59%), and β-turns(1.59%). The tertiary structure of the env protein sequence and the homologous template sequence had 21% similarity in the 408-540 region, and only partial homology modeling could be performed. The env protein has two transmembrane regions and no signal peptides. The env protein contains 20 linear epitopes. The domains 356-442, 490-555, 104-131, 206-230, and 448-469 are the dominant epitope domains of the env protein. The env protein contain 9 N-glycosylation sites, 4 protein kinase C phosphorylation sites, 4 casein kinase II phosphorylation sites, 4 N-myristoylation sites, 1 amidation site, and 1 cell attachment sequence site. Subcellular localization analysis predicted that the env protein is a membrane protein of the ovine pulmonary adenomatosis virus. Conclusion Bioinformatic analysis indicated that the env envelope protein of the Xinjiang strain of an exogenous ovine pulmonary adenomatosis has multiple B cell epitopes and a cell attachment sequence site. These findings provides a theoretical basis for further research on the structure and function of the env protein.