硫醇基团的氧化还原过程对人正常朊蛋白聚集和纤维化特征的影响  

A Redox Process of Ethanethiol Group Increases Formation of β-sheet Structure and Amyloid Fibrils of Wild Type Human Prion Protein

作　　者：孙晗[1,2] 石琦[1] 王绍彬[1] 郭飞[1] 解武玲[1] 陈操[1] 刘存歧[2] 董小平[1] 

机构地区：[1]中国疾病预防控制中心病毒病预防控制所传染病预防控制国家重点实验室,北京102206 [2]河北大学生命科学学院,保定071002

出　　处：《病毒学报》2012年第4期409-413,共5页Chinese Journal of Virology

基　　金：传染病重大专项(2009ZX10004-101);传染病国家重点实验室重点项目(2008SKLID102);传染病国家重点实验室面上项目(2011SKLID211)

摘　　要：本研究旨在通过体外对纯化的原核重组人正常朊蛋白硫醇基团的氧化还原过程,探究二硫键的改变对其生化特性的影响。蛋白沉淀实验显示重组正常人朊病毒蛋白经过硫醇基团的氧化还原过程明显增加了其聚集性;硫磺素T(Thioflavin T,ThT)实验测定发现,经过硫醇基团的氧化还原过程重组PrP蛋白的纤维形成增多;圆二色谱(Circular Dichroism,CD)测定显示,处理后的重组PrP蛋白二级结构发生改变,其β-折叠结构比例显著增多;蛋白酶K消化实验也进一步显示硫醇基团的氧化还原后PrP的蛋白酶K抵抗能力有所增加。这些结果提示二硫键的形成可明显地改变PrP的二级结构,促进朊蛋白聚集和成纤维过程。In order to explore the potential influences of the disulfide bridge on the physical and chemical properties of PrP protein, the expressed recombinant human wild-type PrP protein was purified for using in an established redox process for the reduction and oxidation of the ethanethiol group within PrP. Sedimentation tests illustrated that redox process remarkably promoted the aggregation of recombinant PrP. Thioflavin T binding assay revealed an enhanced fibrillization of the recombinant human PrP after redox process. Far-UV circular dichroism demonstrated that the PrP treated with redox process showed a significant β-sheet rich structure. Furthermore, PrP-specific Western blot identified that the recombinant PrP after redox possessed stronger proteinase K-resistance. Those data indicates that the formation of the disulfide bridge induces the alteration of the secondary structure and enhances the progresses of aggregation and fibrillization of PrP protein.

关 键 词：朊蛋白 氧化还原 纤维化 Β-折叠 

分 类 号：R373.9[医药卫生—病原生物学]