Attractive Protein-Polymer Interactions Markedly Alter the Effect of Macromolecular Crowding on Protein Association Equilibria
Attractive Protein-Polymer Interactions Markedly Alter the Effect of Macromolecular Crowding on Protein Association Equilibria
复制标题
有吸引力的蛋白质-聚合物相互作用显着改变大分子拥挤对蛋白质缔合平衡的影响
DOI：
10.1016/j.bpj.2010.05.013
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发表时间：
2010-08-04
影响因子：
3.4
通讯作者：
Liang, Yi
中科院分区：
文献类型：
--
作者：
Jiao, Ming;Li, Hong-Tao;Liang, Yi
过氧化氢酶的荧光对加入的超氧化物歧化酶（SOD）的浓度的依赖性表明，SOD结合到过氧化氢酶的饱和位点。SOD对这些位点的亲和力随温度和三种标称惰性聚合物添加剂-葡聚糖70、Ficoll 70和聚乙二醇2000中的每一种的浓度而变化。在室温（25.0 ℃）和更高温度下，发现添加高浓度的聚合物显著增强SOD对过氧化氢酶的亲和力，但随着温度降低，添加聚合物的增强作用减弱，并且在8.0 ℃下，添加聚合物对SOD对过氧化氢酶的亲和力几乎没有影响或没有影响。这里提出的结果提供了第一个实验证据之间的排斥体积蛋白质和聚合物之间的相互作用，这往往会增强稀蛋白质的关联，和蛋白质和聚合物之间的相互作用，这往往会抑制蛋白质的关联存在竞争。高浓度的聚合物对蛋白质缔合的净效应取决于在测量温度下这两种类型的相互作用的相对强度，并且在不同的蛋白质和/或聚合物之间可能显著变化。
The dependence of the fluorescence of catalase upon the concentration of added superoxide dismutase (SOD) indicates that SOD binds to saturable sites on catalase. The affinity of SOD for these sites varies with temperature, and with the concentration of each of three nominally inert polymeric additives-dextran 70, Ficoll 70, and polyethylene glycol 2000. At room temperature (25.0 degrees C) and higher, the addition of high concentrations of polymer is found to significantly enhance the affinity of SOD for catalase, but with decreasing temperature the enhancing effect of polymer addition diminishes, and at 8.0 degrees C, addition of polymer has little or no effect on the affinity of SOD for catalase. The results presented here provide the first experimental evidence for the existence of competition between a repulsive excluded volume interaction between protein and polymer, which tends to enhance association of dilute protein, and an attractive interaction between protein and polymer, which tends to inhibit protein association. The net effect of high concentrations of polymer upon protein associations depends upon the relative strength of these two types of interactions at the temperature of measurement, and may vary significantly between different proteins and/or polymers.