【作者】 徐丹；

【导师】 郑清川；

【作者基本信息】 吉林大学 ， 物理化学， 2022， 硕士

【摘要】 流行性感冒病毒(简称流感)在人类中具有高度的传染性,导致从轻度到重度的急性呼吸道传染病肆虐,严重威胁着人类生命的健康和社会经济的发展。根据世界卫生组织的报告,每年流感都会导致约三百万至五百万的严重疾病病例和约两万五千至五万人死亡。人类流感主要由甲型和乙型流感病毒引起,乙型流感病毒引起的疾病占流感病毒的50%,呈现周期性的大爆发。令人遗憾的是,迄今为止尚无有效的靶向乙型流感病毒抑制剂。开发新的流感抗病毒药物是应对未来流感大规模爆发的最有效办法。位于乙型流感病毒表面的非结构蛋白(NS1B)是抵抗宿主先天免疫反应的主要病毒蛋白,被视为抗乙型流感病毒潜在理想药物靶点。NS1B由一个N端结构域(NTD)和一个C端结构域(CTD)组成,两个结构域由一个灵活的多肽连接。在NS1B CTD上存在一个RNA结合位点,与RNA结合是乙型流感病毒复制的先决条件。因此,破坏NS1B CTD与RNA的结合对阻止乙型流感病毒的复制有积极作用。明确NS1B CTD与RNA的结合机制,阐明NS1B CTD突变对其RNA结合活性的影响可为抗乙型流感病毒药物研发提供可靠的理论依据。在本论文中,为了揭示NS1B CTD与RNA的结合机制,明确R156A、K160A、R208A和K221A突变对NS1B CTD和RNA相互作用的影响,我们构建了野生型以及四种突变型的NS1B-dsRNA复合物结构,并进行了分子动力学模拟研究。研究结果表明,氢键作用是稳定NS1B CTD与RNA结合的关键因素。碱性残基突变导致其RNA结合活性降低的主要原因是电荷环境改变引起NS1B CTD构象变化。该项研究丰富了NS1B CTD蛋白的结构特征信息,阐明了NS1B CTD与RNA的结合机制,总结归纳了碱性残基突变导致其RNA结合活性在不同程度上降低的原因。上述结论为靶向NS1B蛋白的抗流感药物研发设计提供了有益的理论线索。更多还原

【Abstract】 Theoretical Study on the Effects of Basic Residue Mutations on the Binding Mechanism between NS1B CTD and RNA Influenza virus(referred to as influenza)is highly contagious in humans,causing acute respiratory infectious diseases to spread from mild to severe,seriously threatening the health of human life and socioeconomic development.As reported from the World Health Organization,the annual influenza epidemics result in about three to five million cases of severe illness and about 25000-50000 deaths.Human influenza is mainly caused by influenza A and B viruses,with influenza B viruses causing about 50%of all influenza virus infections.Regrettably,effective inhibitors targeting influenza B virus have been absent yet.The non-structural protein 1 from influenza B virus(NS1B)plays an important role in countering host antiviral defense,considered as the promising target.NS 1B protein is composed of two domains,a dimer N-terminal domain(NTD)and a C-terminal domain(CTD),joined by a flexible polypeptide linker.Robert M.Krug suggested a novel RNA-binding site on the NS 1B CTD,binding to RNA is prerequisite for optimal replication of influenza B virus.Therefore,disrupting the binding of NS 1B CTD to RNA has a positive effect on attenuating virus replication.Clarifying the binding mechanism of NS 1B CTD to RNA and elucidating the effect of basic residues mutation on its RNA-binding activity has important practical significance for related experimental exploration and drug development.In this thesis,we constructed wild-type and four mutant NS1B-dsRNA complex structures,then carried out molecular dynamics simulation to reveal the binding RNAmechanism of NS 1B CTD and RNA and clarify the effect of R156A,K160A,R208A and K221A mutations on the interaction between NS1B CTD and RNA.The results indicate that the hydrogen bond is the key factor to stable RNA-binding.The main reason for the reduced RNA-binding activity caused by basic residues mutation:changes in the charge environment cause changes in the conformation of NS 1B CTD.This study can enrich the information on the structural characteristics of the NS 1B CTD,elucidate the binding mechanism of NS 1B CTD to RNA,and summarize the reasons why the mutation of basic residues led to the decrease of its RNA binding activity to different degrees.The conclusions mentioned above may provide useful theoretical clues for rational drug design targeting NS 1B protein.更多还原