Strong and Heterogeneous Adsorption of Infectious Bursal Disease VP2 Subviral Particle with Immobilized Metal Ions Dependent on Two Surface Histidine Residues

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• 作者：Shyue-Ru Doong ; Yi-Huei Chen ; Su-Yuan Lai ; Cheng-Chung Lee ; Yu-Chiang Lin ; Min-Ying Wang
• 刊名：Analytical Chemistry
• 出版年：2007
• 出版时间：October 15, 2007
• 年：2007
• 卷：79
• 期：20
• 页码：7654 - 7661
• 全文大小：426K
• 年卷期：v.79,no.20(October 15, 2007)
• ISSN：1520-6882

文摘

VP2, the single outer protein of infectious bursal diseasevirus capsid, can self-assemble into T = 1 subviral particle(SVP), which can be efficiently purified by immobilizedmetal ion affinity chromatography (IMAC). In this study,a systemic investigation of the adsorption behavior of VP2SVP on Ni-NTA resin was performed to identify thatHis253 and His249 on the surface of SVP are the keyfactors accounted for the strong and heterogeneous interaction. First, an untagged VP2-441 SVP was constructed, expressed, and purified by IMAC to demonstratethat SVP can interact with immobilized Ni²⁺ ions on NTAresin without an inserted His tag. Second, equilibriumadsorption studies were used to demonstrate that SVP hasa higher affinity to the immobilized Ni²⁺ ions than a modelprotein, bovine serum albumin, although the maximumamount of SVP bound per volume resin is limited by thepore size of the resin as verified by confocal microscopicanalysis. Third, based on structural analysis and computer modeling, His253 and His249 on the surface ofSVP are responsible for a strong heterogeneous andmultiple adsorption with the immobilized Ni²⁺ ions; andthis was confirmed by a point-mutation experiment. Thisis the first example to elucidate the interaction betweenthe immobilized metal ions and viral particles at molecularlevel. A detailed understanding of SVP-immobilized metalion interactions can provide useful strategies for engineering icosahedral protein nanoparticles to achieve a simpleand one-step purification by IMAC.