Nonmonotonic variation with salt concentration of the second virial coefficient in protein solutions.
Nonmonotonic variation with salt concentration of the second virial coefficient in protein solutions.
复制标题
蛋白质溶液中第二维里系数随盐浓度的非单调变化。
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
A. Louis
中科院分区：
文献类型：
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作者：
E. Allahyarov;H. Löwen;J. Hansen;A. Louis
通过“原始模型”的计算机模拟，在固定pH值下，计算了球状蛋白质溶液的渗透第二维里系数B2随添加盐浓度的变化。盐和反离子以及蛋白质表面的离散电荷模式被明确纳入。对于大致对应溶菌酶的参数，我们发现B2首先随着添加盐浓度的增加而降低，直至达到一个阈值浓度，然后增加到最大值，并且在进一步提高离子强度时再次降低。我们的研究表明，蛋白质表面离散电荷模式的存在对有效相互作用有深远影响，并且线性和非线性泊松 - 玻尔兹曼理论在高离子强度下失效。将观察到的B2的非单调性与实验进行了比较。讨论了对蛋白质结晶的影响。
The osmotic virial coefficient B2 of globular protein solutions is calculated as a function of added salt concentration at fixed pH by computer simulations of the "primitive model." The salt and counterions as well as a discrete charge pattern on the protein surface are explicitly incorporated. For parameters roughly corresponding to lysozyme, we find that B2 first decreases with added salt concentration up to a threshold concentration, then increases to a maximum, and then decreases again upon further raising the ionic strength. Our studies demonstrate that the existence of a discrete charge pattern on the protein surface profoundly influences the effective interactions and that linear and nonlinear Poisson Boltzmann theories fail for large ionic strength. The observed nonmonotonicity of B2 is compared with experiments. Implications for protein crystallization are discussed.