Light scattering and phase behavior of lysozyme-poly(ethylene glycol) mixtures
Light scattering and phase behavior of lysozyme-poly(ethylene glycol) mixtures
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DOI：
10.1103/physrevlett.96.087803
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发表时间：
2006-03-03
影响因子：
8.6
通讯作者：
Fraden, S
中科院分区：
文献类型：
--
作者：
Bloustine, J;Virmani, T;Fraden, S
蛋白质（溶菌酶）和聚合物，聚（乙二醇）（PEG）的混合物的液-液相变温度（浊点）的测量表明，低分子量PEG的加入稳定的混合物，而高分子量PEG是不稳定的。我们证明，这种行为是不一致的熵溶菌酶PEG耗尽相互作用，并建议，一个充满活力的溶菌酶PEG吸引力负责。为了独立地表征溶菌酶-PEG相互作用，对相同的混合物进行光散射实验以测量第二维里系数和第三维里系数。这些测量结果表明，PEG诱导溶菌酶分子之间的排斥，相反的耗尽预测。此外，它表明，第三维里项必须包括在混合物的自由能，以定性地捕捉我们的数据。
Measurements of liquid-liquid phase transition temperatures (cloud points) of mixtures of a protein (lysozyme) and a polymer, poly(ethylene glycol) (PEG) show that the addition of low molecular weight PEG stabilizes the mixture whereas high molecular weight PEG was destabilizing. We demonstrate that this behavior is inconsistent with an entropic lysozyme-PEG depletion interaction and suggest that an energetic lysozyme-PEG attraction is responsible. In order to independently characterize the lysozyme-PEG interactions, light scattering experiments on the same mixtures were performed to measure second and third virial coefficients. These measurements indicate that PEG induces repulsion between lysozyme molecules, contrary to the depletion prediction. Furthermore, it is shown that third virial terms must be included in the mixture's free energy in order to qualitatively capture our data.