新型鸭呼肠孤病毒QY株σB蛋白基因特征、二级结构预测及其细胞抗原表位分析

Analysis for Characteristics of the New-type Duck Reovirus σB Protein and Prediction of Secondary Structure and B- and T-cell Epitopes

本研究旨在对新型鸭呼肠孤病毒(NDRV)QY株σB蛋白的遗传变异规律和结构及功能进行分析。从GenBank数据库中获取QY株和25株参考株的σB蛋白编码序列,通过Mega 6.0软件进行序列比对分析和系统进化树构建;使用Datamonkey软件进行选择压力分析;运用生物信息学软件预测QY株σB蛋白二级结构功能及B细胞和T细胞抗原表位。相似性分析结果显示,NDRV QY株与国内其他地区分离的鸭呼肠孤病毒(DRV)氨基酸相似性达到94.9%~98.9%,与禽呼肠孤病毒(ARV)及番鸭呼肠孤病毒(MDRV)的相似性仅为66.5%~68.4%和67.6%~68.4%;选择压力分析显示,σB蛋白承受净化选择压力,但存在一个正向选择位点;σB蛋白属于亲水蛋白,不具有信号肽和跨膜区,含有潜在的O-糖基化位点;结构预测分析显示,σB蛋白具有α-螺旋、β-折叠、β-转角及无规则卷曲等丰富的二级结构;表位分析显示,σB蛋白含有潜在的B细胞和T细胞抗原表位。本研究成功进行了QY株σB蛋白的基因特征和结构功能预测及其细胞表位分析,为深入了解该蛋白的免疫学特性及研发NDRV新型疫苗奠定了基础。

The purpose of this study was to analyze the genetic variation,structure and function ofσB protein of a new duck reovirus(NDRV)QY strain.The coding sequences ofσB protein of QY strain and 25 reference strains were obtained from GenBank database.Sequence alignment analysis and phylogenetic tree construction were carried out by Mega 6.0 software.Selective pressure analysis was carried out by Datamonkey software.Secondary structure and function ofσB protein of QY strain and antigen epitopes of B and T cells were predicted by bioinformatics software.Similarity analysis showed that the amino acid similarity of NDRV QY strain with duck reovirus(DRV)isolated from other regions in China reached 94.9%to 98.9%,and the similarity with avian reovirus(ARV)and Muscovy duck reovirus(MDRV)were only 66.5%to 68.4%and 67.6%to 68.4%,respectively.Selective pressure analysis showed thatσB protein was subjected to purification selective pressure,but one positively selected site was detected.TheσB protein belonged to hydrophilic protein,had no signal peptide and transmembrane region,and contained potential O-glycosylation sites.Structural prediction analysis showed thatσB protein had abundant secondary structures such as alpha helix,beta fold,beta turn and random coil.Epitope analysis showed thatσB protein contained potential B-and T-cell epitopes.This study successfully predicted the gene characteristics,structure and function ofσB protein of QY strain and analyzed its cell epitope,which laid a foundation for further understanding the immunological characteristics of the protein and developing a new NDRV vaccine.