论文标题
蛋白质介电常数的变化
Variations in Proteins Dielectric Constants
论文作者
论文摘要
使用一种新的半经验方法来计算分子极化和Clausius Mossotti关系，我们计算了蛋白质数据库（PDB）中所有结构的干蛋白的静态介电常数。超过150,000个蛋白质的平均介电常数为3.23，标准偏差为0.04，这与先前对干蛋白的测量非常吻合。较小的标准偏差是由于分子极化性与蛋白质体积之间的强相关性而产生的。我们注意到，非氨基酸辅因子（例如叶绿素）可能会显着改变介电环境。此外，我们的模型根据组成氨基酸和辅因子显示了同一分子内介电常数的各向异性。最后，通过改变氨基酸质子化状态，我们表明pH的变化对蛋白质的介电常数没有显着影响。
Using a new semi empirical method for calculating molecular polarizabilities and the Clausius Mossotti relation, we calculated the static dielectric constants of dry proteins for all structures in the protein data bank (PDB). The mean dielectric constant of more than 150,000 proteins is 3.23 with a standard deviation of 0.04, which agrees well with previous measurement for dry proteins. The small standard deviation results from the strong correlation between the molecular polarizability and the volume of the proteins. We note that non amino acid cofactors such as Chlorophyll may alter the dielectric environment significantly. Furthermore, our model shows anisotropies of the dielectric constant within the same molecule according to the constituent amino acids and cofactors. Finally, by changing the amino acid protonation states, we show that a change of pH does not have a significant effect on the dielectric constants of proteins.
