EXPERIMENTALLY DERIVED POINT CHARGES FOR PROTEINS

我们建议测定常见氨基的原子部分电荷。 酸，蛋白质的组成成分，来自实验数据。这些 电荷是分子中使用的力场的必要参数 蛋白质的模型化研究。以前，这样的费用已经推导出来 运用量子力学等理论技术。自.以来 蛋白质的能量和构象被认为是非常重要的 受这些分子内的电荷相互作用的影响，它非常 重要的是，分子力学中使用的电荷参数和 动力学计算要尽可能准确。使用最近派生的 方法，我们现在能够从高精度推导出必要的电荷 X射线结晶学数据。如此确定的指控将适用于一些 用途，包括：1)它们将用于改进的力场 用于未来的蛋白质分子模型研究；以及2)它们将服务于 作为对照数据集，用来比较理论上的结果 电荷计算。通过比较电荷集合，我们可以改进 理论技巧(最优基数集的确定、会计 氢键的影响等)，最终使这些方法 在以下情况下进行电荷测定更可靠 实验测定是不可行的。

We propose to determine atomic partial charges for commonly occurring amino acids, the building blocks of proteins, from experimental data. These charges are necessary parameters for the force fields used in molecular modeling studies of proteins. Previously, such charges have been derived using quantum mechanical and other theoretical techniques. Since the energies, and thus conformations, of proteins are believed to be heavily influenced by charge-charge interactions within these molecules, it is very important that the charge parameters used in molecular mechanics and dynamics calculations be as accurate as possible. Using recently derived methods, we are now able to derive the necessary charges from high accuracy x-ray crystallographic data. The charges so determined will serve a number of purposes, including: 1) They will be used in an improved force field for future molecular modeling studies of proteins; and 2) They will serve as a control set of data with which to compare the results of theoretical charge calculations. By comparing charge sets, we can improve the theoretical techniques (determination of an optimal basis set, accounting for the effects of hydrogen bonding, etc.), ultimately making these methods more reliable for charge determinations in those cases for which an experimental determination is infeasible.