番木瓜环斑病毒(Papaya ringspot virus,PRSV)编码的核内涵体蛋白a蛋白酶(Nuclear inclusion body a proteinase,NIa-Pro)是一种多功能病毒非结构蛋白,在病毒侵染宿主及病毒与宿主互作中起着重要作用。本研究利用以麦芽糖结合蛋白(MBP)...番木瓜环斑病毒(Papaya ringspot virus,PRSV)编码的核内涵体蛋白a蛋白酶(Nuclear inclusion body a proteinase,NIa-Pro)是一种多功能病毒非结构蛋白,在病毒侵染宿主及病毒与宿主互作中起着重要作用。本研究利用以麦芽糖结合蛋白(MBP)为融合表达框架的原核表达系统构建了表达NIa-Pro的重组载体pMAL-c5xNP,并转化大肠杆菌,经IPTG诱导和Ni^(2+)-NTA-琼脂糖亲和层析纯化获得了可溶的重组融合蛋白MBP-NIa(N端和C端分别融合MBP和His标签),然后利用蛋白酶Factor Xa切去重组融合蛋白中的MBP,再通过直链淀粉树脂亲和层析纯化获得了可溶的重组蛋白NIa-Pro。活性检测结果表明,重组蛋白PRSV-NIa-Pro具有非特异的双链DNA酶和特异的蛋白酶双重活性。展开更多
Background:Computer simulation studies complement in vitro experiments and provide avenue to understand allosteric regulation in the absence of other molecular viewing techniques.Molecular dynamics captures internal m...Background:Computer simulation studies complement in vitro experiments and provide avenue to understand allosteric regulation in the absence of other molecular viewing techniques.Molecular dynamics captures internal motion within the protein and enables tracing the communication path between a catalytic site and a distal allosteric site.In this article,we have identified the communication pathway between the viral protein genome linked(VPg)binding region and catalytic active site in nuclear inclusion protein-a protease(NIa-Pro).Methods:Molecular dynamics followed by in silico analyses have been used to map the allosteric pathway.Results:This study delineates the residue interaction network involved in allosteric regulation of NIa-Pro activity by VPg.Simulation studies indicate that point mutations in the VPg interaction interface of NIa-Pro lead to disruption in these networks and change the orientation of catalytic residues.His142Ala and His167Ala mutations do not show a substantial change in the overall protease structure,but rather in the residue interaction network and catalytic site geometry.Conclusion:Our mutagenic study delineates the allosteric pathway and facilitates the understanding of the modulation of NIa-Pro activity on a molecular level in the absence of the structure of its complex with the known regulator VPg.Additionally,our in silico analysis explains the molecular concepts and highlights the dynamics behind the previously reported wet lab study findings.展开更多
文摘番木瓜环斑病毒(Papaya ringspot virus,PRSV)编码的核内涵体蛋白a蛋白酶(Nuclear inclusion body a proteinase,NIa-Pro)是一种多功能病毒非结构蛋白,在病毒侵染宿主及病毒与宿主互作中起着重要作用。本研究利用以麦芽糖结合蛋白(MBP)为融合表达框架的原核表达系统构建了表达NIa-Pro的重组载体pMAL-c5xNP,并转化大肠杆菌,经IPTG诱导和Ni^(2+)-NTA-琼脂糖亲和层析纯化获得了可溶的重组融合蛋白MBP-NIa(N端和C端分别融合MBP和His标签),然后利用蛋白酶Factor Xa切去重组融合蛋白中的MBP,再通过直链淀粉树脂亲和层析纯化获得了可溶的重组蛋白NIa-Pro。活性检测结果表明,重组蛋白PRSV-NIa-Pro具有非特异的双链DNA酶和特异的蛋白酶双重活性。
文摘Background:Computer simulation studies complement in vitro experiments and provide avenue to understand allosteric regulation in the absence of other molecular viewing techniques.Molecular dynamics captures internal motion within the protein and enables tracing the communication path between a catalytic site and a distal allosteric site.In this article,we have identified the communication pathway between the viral protein genome linked(VPg)binding region and catalytic active site in nuclear inclusion protein-a protease(NIa-Pro).Methods:Molecular dynamics followed by in silico analyses have been used to map the allosteric pathway.Results:This study delineates the residue interaction network involved in allosteric regulation of NIa-Pro activity by VPg.Simulation studies indicate that point mutations in the VPg interaction interface of NIa-Pro lead to disruption in these networks and change the orientation of catalytic residues.His142Ala and His167Ala mutations do not show a substantial change in the overall protease structure,but rather in the residue interaction network and catalytic site geometry.Conclusion:Our mutagenic study delineates the allosteric pathway and facilitates the understanding of the modulation of NIa-Pro activity on a molecular level in the absence of the structure of its complex with the known regulator VPg.Additionally,our in silico analysis explains the molecular concepts and highlights the dynamics behind the previously reported wet lab study findings.
