This investigation examines the validity of employing single-solute theory to interpret SAXS measurements on buffered protein solutions-the current practice despite the necessity to regard the buffer components as additional non-scattering solutes rather than as part of the solvent. The present study of bovine serum albumin in phosphate-buffered saline supplemented with 20-100 g/L sucrose as small cosolute has certainly verified the prediction that the experimentally obtained second virial coefficient should contain protein-cosolute contributions. Nevertheless, the second virial coefficient determined for protein solutions supplemented with high cosolute concentrations on the basis of single-solute theory remains a valid means for identifying conditions conducive to protein crystallization, because the return of a slightly negative second virial coefficient based on single-solute theory [Formula: see text] still establishes the existence of slightly associative interactions between protein molecules, irrespective of the molecular source-protein self-interactions and/or protein-cosolute contributions.

中文翻译：

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小角度X射线散射实验确定第二维里系数：一个问题。

这项研究检验了使用单溶质理论解释缓冲蛋白溶液上SAXS测量的有效性-尽管需要将缓冲液成分视为其他非散射溶质而不是溶剂的一部分，但目前的做法是。目前对牛血清白蛋白在磷酸盐缓冲液中添加20-100 g / L蔗糖作为小溶质的研究，确实证实了以下预测：实验获得的第二病毒系数应包含蛋白溶质。尽管如此，根据单溶质理论确定的添加高固溶物浓度的蛋白质溶液的第二病毒系数仍然是鉴定有助于蛋白质结晶的条件的有效手段，