摘要
目的 了解广东省甲型H1N1pdm流感病毒聚合酶碱性蛋白2(polymerase basic protein 2,PB2)基因变异株的分子特征,探讨其特异性分子位点,为流感病毒防控提供科学依据.方法 采集感染PB2基因变异株的2例病例咽拭子标本进行病毒分离,并挑选23株广东省流感病毒株进行测序分析,利用GISAID提供的参考序列和疫苗株序列对血凝素(hemagglutinin,HA)和PB2基因进行进化分析;开展毒株抗原分析和神经氨酸酶(neuraminidase,NA)抑制试验;构建PB2蛋白模型,分析聚合酶活性.结果 PB2-D701N和PB2-A271S变异株HA基因出现H399N氨基酸位点突变,均属于6B.1A.5a.2a分支;与疫苗株A/Victoria/4897/2022同属大分支不同小分支,均为疫苗类似株.在三维结构中,PB2-D701N和PB2-A271S突变发生电荷改变和亲疏水变化.结论 PB2-D701和A271高度保守,PB2突变株尚未成为优势株,但其抗原性与疫苗匹配性高,对NA抑制剂敏感.三维模型推测,PB2-D701N突变可增强病毒的致病力而影响传播能力,PB2-A271S则可能影响流感病毒的聚合酶活性和聚合酶复合物的合成.
Abstract
Objective To understand the molecular characteristics of the mutant strain of polymerase basic protein 2(PB2)gene of influenza A(H1N1pdm)in Guangdong province,and to explore its specific molecular sites,so as to provide scientific basis for the prevention and control of influenza virus.Methods Throat swab samples were collected from 2 cases infected with PB2 gene variant strains for virus isolation,and 23 influenza virus strains were selected from Guangdong province for sequencing analysis.The reference sequences and vaccine strain sequences provided by GISAID were used to perform evolutionary analysis on hemagglutinin(HA)and PB2 genes.Virus strain antigen analysis and neuraminidase(NA)inhibition test were carried out.PB2 protein model was constructed and polymerase activity was analyzed.Results H399N amino acid mutation occurred in the HA gene of PB2-D701N and PB2-A271S variant strains,both of which belonged to the branch of 6B.1A.5a.2a.They belonged to the same big branch and different small branches as the vaccine strain A/Victoria/4897/2022,and they are all vaccine-like strains.In the three-dimensional structure,the mutations of PB2-D701N and PB2-A271S change charge and hydrophobicity.Conclusions PB2-D701 and A271 were highly conserved,and PB2 mutant strains were not the dominant strains.The PB2 mutant had high antigenicity with the vaccine.The PB2 mutant strain is sensitive to NA inhibitors.The three-dimensional model predicted that PB2-D701N mutation could enhance virulence and affect transmissibility of influenza virus,while PB2-A271S mutation could affect polymerase activity and polymerase complex synthesis of influenza virus.
基金项目
广东省医学科学技术研究基金(C2022012)
中医药多学科交叉创新项目(ZYYCXTU-D-202203)
广东省新发传染病应急检测技术研究与应用重点实验室(2023B1212010010)
NETL
NSTL
万方数据