Gitlin Irina, Carbeck Jeffrey D, Whitesides George M
Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford St., Cambridge, MA 02138, USA.
Angew Chem Int Ed Engl. 2006 May 5;45(19):3022-60. doi: 10.1002/anie.200502530.
Almost all proteins contain charged amino acids. While the function in catalysis or binding of individual charges in the active site can often be identified, it is less clear how to assign function to charges beyond this region. Are they necessary for solubility? For reasons other than solubility? Can manipulating these charges change the properties of proteins? A combination of capillary electrophoresis (CE) and protein charge ladders makes it possible to study the roles of charged residues on the surface of proteins outside the active site. This method involves chemical modification of those residues to generate a large number of derivatives of the protein that differ in charge. CE separates those derivatives into groups with the same number of modified charged groups. By studying the influence of charge on the properties of proteins using charge ladders, it is possible to estimate the net charge and hydrodynamic radius and to infer the role of charged residues in ligand binding and protein folding.
几乎所有蛋白质都含有带电荷的氨基酸。虽然活性位点中单个电荷在催化或结合方面的功能通常可以确定，但对于如何将功能赋予该区域之外的电荷却不太清楚。它们对溶解度是必需的吗？是出于溶解度之外的其他原因吗？操纵这些电荷会改变蛋白质的性质吗？毛细管电泳（CE）和蛋白质电荷阶梯的结合使得研究活性位点之外蛋白质表面带电荷残基的作用成为可能。该方法涉及对那些残基进行化学修饰，以生成大量电荷不同的蛋白质衍生物。CE将那些衍生物分离成具有相同数量修饰电荷基团的组。通过使用电荷阶梯研究电荷对蛋白质性质的影响，可以估计净电荷和流体动力学半径，并推断带电荷残基在配体结合和蛋白质折叠中的作用。
