SOLUBILITY DIAGRAM ANALYSIS AND THE RELATIVE EFFECTIVENESS OF DIFFERENT IONS ON PROTEIN CRYSTAL GROWTH
SOLUBILITY DIAGRAM ANALYSIS AND THE RELATIVE EFFECTIVENESS OF DIFFERENT IONS ON PROTEIN CRYSTAL GROWTH
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DOI：
10.1016/s1046-2023(05)80143-4
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发表时间：
1990-01-01
期刊：
影响因子：
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通讯作者：
RIES-KAUTT M M
中科院分区：
文献类型：
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作者：
DUCRUIX A F;RIES-KAUTT M M
蛋白质的溶解度可以定义为在给定的pH、温度、缓冲液和/或各种添加剂的条件下与固相平衡的可溶性蛋白质的浓度。溶解度曲线表示该饱和浓度对单个参数的依赖性，该参数可以是结晶剂或沉淀剂的浓度。为了准确测定，溶解度应通过晶体的结晶和再溶解来测定，并且应证明在两种方法中蛋白质浓度渐近收敛到相同值。在容易获得相当大量蛋白质的情况下，溶解度图分析提供了一种定量表征一个参数的影响的方法，从而以有意义的方式解释其影响。我们对各种盐存在下、pH 4.5 和 18°C 下的溶菌酶 (pl = 11.1) 溶解度曲线进行了分析。 C，表明溶解度受阴离子的影响大于阳离子，并且阴离子的有效性的顺序与霍夫迈斯特级数的顺序大致相反。在这些条件下，硫氰酸盐（高浓度的离液阴离子）被发现在低浓度（< 0.1 M）下是非常有效的结晶剂。另外两种高等电点单体蛋白（埃拉布毒素和牛胰蛋白酶抑制剂）也在 pH 4.5 和 18°C 下结晶。 C，证实 KSCN 比 NaCl 具有更高的有效性。溶解度曲线和上方仅发生沉淀的曲线之间的结晶区宽度也随不同阴离子而有很大变化。这些观察结果可能对筛选和优化结晶条件具有有用的意义。
The solubility of a protein can be defined as the concentration of the soluble protein in equilibrium with the solid phase under given conditions of pH, temperature, buffer, and/or various additives. A solubilility curve represents the dependence of this saturating concentration on a single parameter, which could be the concentration of a crystallizing or precipitating agent. For accurate determinations, the solubility should be determined by both crystallization and redissolution of crystals, and it should be demonstrated that in the two methods the protein concentration converges asymptotically to the same value. In cases where fairly large amounts of protein are readily available, solubility diagram analysis provides a means of quantitatively characterizing the effect of one parameter, and hence of interpreting its influence in a meaningful way. Our analysis of lysozyme (pl = 11.1) solubility curves in presence of various salts, at pH 4.5 and 18.degree. C, indicates that solubility is affected more by anions than by cations and that the effectiveness of the anions is in an order roughly the reverse of that of the Hofmeister series. Under these conditions, thiocyanate, a chaotropic anion at high concentration, is found to be a very effective crystallizing agent at low (< 0.1 M) concentrations. Two other monomeric proteins (erabutoxin and bovine pancreatic trypsin inhibitor) of high isoelectric point crystallized also at pH 4.5 and 18.degree. C, confirming the much higher effectiveness of KSCN compared to NaCl. The width of the crystallization zone between the solubility curve and the curve above which only precipitation occurs also varies considerably with different anions. These observations may have useful implications in screening and optimizing crystallization conditions.