Protein cluster formation in aqueous solution in the presence of multivalent metal ions--a light scattering study.
Protein cluster formation in aqueous solution in the presence of multivalent metal ions--a light scattering study.
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DOI：
10.1039/c3sm52447g
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发表时间：
2014-01
期刊：
影响因子：
3.4
通讯作者：
Daniel Soraruf;F. Roosen‐Runge;M. Grimaldo;F. Zanini;R. Schweins;T. Seydel;Fajun Zhang;R. Roth;M. Oettel;F. Schreiber
中科院分区：
文献类型：
--
作者：
Daniel Soraruf;F. Roosen‐Runge;M. Grimaldo;F. Zanini;R. Schweins;T. Seydel;Fajun Zhang;R. Roth;M. Oettel;F. Schreiber
作为结晶和相分离前体的蛋白质簇的形成是蛋白质科学中的基础和实际兴趣。使用多价离子，远程库仑排斥和短程吸引的强度可以在蛋白质溶液中进行调整，代表一个控制良好的模型系统，以研究从电荷稳定到聚集状态过渡期间的静态和动态特性。在这里，我们研究的可压缩性，扩散，和溶质的大小通过静态（SLS）和动态光散射（DLS）在牛血清白蛋白（BSA）和YCl 3的解决方案。对于这种和类似的系统，增加筛选和最终反转的蛋白质表面电荷诱导丰富的相行为，包括再入冷凝，液-液相分离和结晶，这使得簇形成的背景下的前体形成和成核的液体和结晶相。我们发现，接近混浊的聚集体政权增加盐浓度CS，扩散系数降低和散射强度增加的数量级，证明增加相关长度可能与聚类。静态和动态观察的组合表明形成的BSA簇的大小为100 nm的顺序。全球热力学状态似乎至少在几个小时内是稳定的。令人惊讶的是，从不同的蛋白质浓度的集体扩散和逆压缩性的结果可以重新缩放到主曲线作为cs/c* 的函数，其中c* 是过渡到混浊的聚集体制度的临界盐浓度。
The formation of protein clusters as precursors for crystallization and phase separation is of fundamental and practical interest in protein science. Using multivalent ions, the strengths of both long-range Coulomb repulsion and short-range attraction can be tuned in protein solutions, representing a well-controlled model system to study static and dynamic properties of clustering during the transition from a charge-stabilized to an aggregate regime. Here, we study compressibility, diffusion, and size of solutes by means of static (SLS) and dynamic light scattering (DLS) in solutions of bovine serum albumin (BSA) and YCl3. For this and comparable systems, an increasing screening and ultimately inversion of the protein surface charge induce a rich phase behavior including reentrant condensation, liquid-liquid phase separation and crystallization, which puts the cluster formation in the context of precursor formation and nucleation of liquid and crystalline phases. We find that, approaching the turbid aggregate regime with increasing salt concentration cs, the diffusion coefficients decrease and the scattered intensity increases by orders of magnitude, evidencing increasing correlation lengths likely associated with clustering. The combination of static and dynamic observations suggests the formation of BSA clusters with a size on the order of 100 nm. The global thermodynamic state seems to be stable over at least several hours. Surprisingly, results on collective diffusion and inverse compressibility from different protein concentrations can be rescaled into master curves as a function of cs/c*, where c* is the critical salt concentration of the transition to the turbid aggregate regime.