Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan.
Faculty of Pharmaceutical Sciences, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan; Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba, 278-8510, Japan.
Colloids Surf B Biointerfaces. 2020 Jun;190:110845. doi: 10.1016/j.colsurfb.2020.110845. Epub 2020 Feb 14.
In this study, the combined effects of pH and salt concentration on the aggregation and amyloid formation of a charge-bearing protein (hen egg white lysozyme, HEWL) were investigated, as well as the inhibition of amyloid formation by using dithiothreitol (DTT) as a denaturing agent. Amyloid formation was found to depend on the ion strength and pH of the sample solution. Rather than the total charge, the partial charge of the amyloid related residues contributes to amyloid formation at pH < isoelectric point (pI). On the other hand, at pH> pI HEWL only undergoes alkaline denaturation regardless of the ionic strength. The effect of adding different amounts of DTT at different times on amyloid formation was also investigated. These results suggested that the positions of charges on a protein and the protein secondary structure are critical for protein aggregation and amyloid formation.
在这项研究中，考察了 pH 值和盐浓度对带电蛋白（鸡卵清白溶菌酶，HEWL）聚集和淀粉样纤维形成的联合影响，以及使用二硫苏糖醇（DTT）作为变性剂抑制淀粉样纤维形成的情况。结果发现，淀粉样纤维的形成取决于样品溶液的离子强度和 pH 值。在 pH 值<等电点（pI）时，与淀粉样纤维相关的残基的部分电荷而不是总电荷有助于淀粉样纤维的形成。另一方面，在 pH 值>pI 时，无论离子强度如何，HEWL 仅经历碱性变性。还研究了在不同时间添加不同量的 DTT 对淀粉样纤维形成的影响。这些结果表明，蛋白质上电荷的位置和蛋白质二级结构对蛋白质聚集和淀粉样纤维形成至关重要。
