Carbonnaux C, Ries-Kautt M, Ducruix A
Laboratoire de Biologie Structurale, CNRS-Université Paris Sud, Gif-Sur-Yvette, France.
Protein Sci. 1995 Oct;4(10):2123-8. doi: 10.1002/pro.5560041018.
The effects of various anions on decreasing the solubility of acidic Hypoderma lineatum collagenase at pH 7.2 and 18 degrees C were qualitatively defined by replacing the crystallizing agent of known crystallization conditions by various ammonium salts. The solubility curves measured in the presence of the sulfate, phosphate, citrate, and chloride ammonium salts gave the following ranking of anions: HPO4(2-)/H2PO4- > SO4(2-) > citrate 3-/citrate2- >> Cl-. This order is in agreement with the Hofmeister series. In a previous study on the solubility at pH 4.5 of lysozyme, a basic protein, the effectiveness of anions in decreasing the solubility was found to be in the reverse order. This suggests that the effectiveness of anions in the crystallization of proteins is dependent on the net charge of the protein, i.e., depending on whether a basic protein is crystallized at acidic pH or an acidic protein at basic pH.
通过用各种铵盐替代已知结晶条件下的结晶剂，定性地确定了各种阴离子在pH 7.2和18℃下降低酸性皮蝇胶原酶溶解度的效果。在硫酸铵、磷酸铵、柠檬酸铵和氯化铵存在下测得的溶解度曲线给出了以下阴离子排序：HPO4(2-)/H2PO4- > SO4(2-) > 柠檬酸3-/柠檬酸2- >> Cl-。这个顺序与霍夫迈斯特序列一致。在先前关于碱性蛋白质溶菌酶在pH 4.5时溶解度的研究中，发现阴离子降低溶解度的有效性顺序相反。这表明阴离子在蛋白质结晶中的有效性取决于蛋白质的净电荷，即取决于碱性蛋白质是在酸性pH下结晶还是酸性蛋白质在碱性pH下结晶。
