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利用生物信息学软件和数据库研究南宁市2009~2012年度A(H3N2)亚型流感病HA基因的遗传变异规律及蛋白结构变化。通过RT-PCR扩增H3N2病毒HA基因并测序,同源比对统计毒株氨基酸位点的差异、构建系统进化树分析进化规律和同源建模分析蛋白结构的变化。系统进化树表明53株HA基因序列被分为4个类群,呈多侧支流行;所有毒株的二硫键和受体结合位点(RBS)高度保守;部分毒株HA在第45位点增加一个糖基化位点,在第144位点丢失一个糖基化位点;HA抗原决定簇氨基酸累计有30个位点发生变异,涉及5个抗原决定簇;HA晶体结构分析抗原决定簇突变位点主要发生在无规则卷曲处,大多数替换的氨基酸种类和性质相同或相似。南宁市A(H3N2)亚型流感病毒株变异活跃,2012年A(H3N2)亚型流感病毒与当年WHO推荐的疫苗株具有较远的进化距离,多数毒株具备了形成新变种的条件,是否形成新的流行株,有待深入研究。
Bioinformatics software and database were used to study the genetic variation and protein structure of HA gene of influenza A (H3N2) subtype in Nanning from 2009 to 2012. The HA gene of H3N2 virus was amplified by RT-PCR and sequenced. The homology comparison was used to analyze the differences in amino acid sites of the strain and the evolutionary rules of the phylogenetic tree were analyzed. The changes of protein structure were analyzed by homology modeling. The phylogenetic tree indicated that the 53 HA gene sequences were divided into four groups and showed multi-lateral branch flow. The disulfide bond and receptor binding site (RBS) of all the strains were highly conserved. A glycosylation site was added and a glycosylation site was lost at position 144. A total of 30 amino acid residues in the HA epitope were mutated and involved five epitopes; HA crystal structure analysis of the epitope mutation Sites occur predominantly at random curls, with most of the identical and similar amino acid species and properties replaced. The influenza A (H3N2) subtype influenza virus strain in Nanning City is highly variable. In 2012, the influenza A (H3N2) subtype influenza virus had far evolutionary distance from the vaccine strains recommended by the WHO in that year. Most of the strains had the conditions to form new variants, The formation of a new epidemic strain, pending further study.