Decrease in pH destabilizes individual vault nanocages by weakening the inter-protein lateral interaction
Decrease in pH destabilizes individual vault nanocages by weakening the inter-protein lateral interaction
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DOI：
10.1038/srep34143
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发表时间：
2016-10-14
影响因子：
4.6
通讯作者：
de Pablo, Pedro J.
中科院分区：
文献类型：
--
作者：
Llauro, Aida;Guerra, Pablo;de Pablo, Pedro J.
穹窿颗粒是天然存在的蛋白质笼，具有作为分子容器的有前景的应用。使用拱顶作为功能性运输工具需要对其结构稳定性有深刻的理解，以保证保护和有效载荷的受控交付。以前的结果进行散装技术或在非生理条件下建议pH值作为一个参数来控制拱顶动态。在这里，我们使用原子力显微镜（AFM）监测结构演变的个别拱顶颗粒，同时改变pH值在真实的时间。我们的实验表明，降低溶液的pH值的不稳定的桶区域，拱顶颗粒的中心部分，并导致聚集的笼。使用石英晶体微天平（QCM）和差示扫描荧光法（DSF）的其他分析与我们的单分子AFM实验一致。观察到的地形缺陷表明，低pH值削弱了相邻蛋白质之间的键。我们推测，所观察到的影响是与强极性的蛋白质-蛋白质的横向相互作用。总的来说，我们的研究揭示了生物相关的pH值范围对拱顶颗粒的稳定性和动力学的影响机制。
Vault particles are naturally occurring proteinaceous cages with promising application as molecular containers. The use of vaults as functional transporters requires a profound understanding of their structural stability to guarantee the protection and controlled payload delivery. Previous results performed with bulk techniques or at non-physiological conditions have suggested pH as a parameter to control vault dynamics. Here we use Atomic Force Microscopy (AFM) to monitor the structural evolution of individual vault particles while changing the pH in real time. Our experiments show that decreasing the pH of the solution destabilize the barrel region, the central part of vault particles, and leads to the aggregation of the cages. Additional analyses using Quartz-Crystal Microbalance (QCM) and Differential Scanning Fluorimetry (DSF) are consistent with our single molecule AFM experiments. The observed topographical defects suggest that low pH weakens the bonds between adjacent proteins. We hypothesize that the observed effects are related to the strong polar character of the protein-protein lateral interactions. Overall, our study unveils the mechanism for the influence of a biologically relevant range of pHs on the stability and dynamics of vault particles.