Dynamics of Macromolecular Assembly Section, Laboratory of Cellular Imaging and Macromolecular Biophysics, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, 13 South Drive, Bldg. 13, Rm 3N17, Bethesda, Maryland, 20892, USA.
AAPS J. 2019 Feb 27;21(3):35. doi: 10.1208/s12248-019-0307-0.
The study of weak or colloidal interactions of therapeutic proteins in different formulations allows prediction and optimization of protein stability. Various biophysical techniques have been applied to determine the second osmotic virial coefficient B as it reflects on the macromolecular distance distribution that governs solution behavior at high concentration. In the present work, we exploit a direct link predicted by hydrodynamic theory between B and the nonideality of sedimentation, commonly measured in sedimentation velocity analytical ultracentrifugation through the nonideality coefficient of sedimentation, k. Using sedimentation equilibrium analytical ultracentrifugation for independent measurement of B, we have examined the dependence of k on B for model proteins in different buffers. The data exhibit the expected linear relationship and highlight the impact of protein shape on the magnitude of the nonideality coefficient k. Recently, measurements of k have been considerably simplified allowing higher throughput and simultaneous polydispersity assessment at higher protein concentrations. Thus, sedimentation velocity may offer a useful approach to compare the impact of formulation conditions on weak interactions and simultaneously on higher-order structure of therapeutic proteins.
研究不同制剂中治疗性蛋白质的弱相互作用或胶体相互作用，可以预测和优化蛋白质的稳定性。已经应用了各种生物物理技术来确定第二渗透压第二维里系数 B，因为它反映了控制高浓度溶液行为的大分子距离分布。在本工作中，我们利用流体力学理论预测的 B 与沉降非理想性之间的直接联系，通常通过沉降速度分析超速离心通过沉降非理想系数 k 来测量。通过沉降平衡分析超速离心法独立测量 B，我们考察了不同缓冲液中模型蛋白质的 k 对 B 的依赖性。数据显示出预期的线性关系，并突出了蛋白质形状对非理想系数 k 大小的影响。最近，k 的测量已经大大简化，允许在更高的蛋白质浓度下进行更高的通量和同时的多分散性评估。因此，沉降速度分析可能是一种有用的方法，可以比较制剂条件对弱相互作用的影响，同时对治疗性蛋白质的高级结构产生影响。
