Molecular electrostatic potentials from crystal diffraction: the neurotransmitter gamma-aminobutyric acid.
Molecular electrostatic potentials from crystal diffraction: the neurotransmitter gamma-aminobutyric acid.
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晶体衍射的分子静电势：神经递质 γ-氨基丁酸。
DOI：
10.1016/s0006-3495(93)81142-1
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发表时间：
1993
影响因子：
3.4
通讯作者：
Craven,BM
中科院分区：
文献类型：
--
作者：
Stewart,RF;Craven,BM
给定从晶体中电荷密度分布的衍射研究获得的电子电荷参数，提出了用于推导静电势的数学过程。该过程允许绘制从晶体结构中移除的分子或分子组的静电势图，但每个分子由于原始晶体环境而保留极化效应。该方法适用于神经递质γ-氨基丁酸。 γ-氨基丁酸分子的潜力是根据一个简单的模型进行分析的，该模型适合与库仑分子相互作用相关的快速计算。在距原子核 1.2 A 的分子包膜外，总电势由球形原子贡献之和很好地表示，其中 V(r) = (q/r) + exp(-beta r2)。势能中最重要的非球面成分是氢原子的偶极子贡献。这可以表示为 V(r, phi) = (0.162 cos phi)/(r2 + 0.615)。这里，V 的单位是 e/A，r 是距 A 中每个原子核的距离，q 是实验确定的以电子单位表示的原子净电荷，phi 是 r 与键 X-H 之间的角度。我们分别得到 C、N 和 O 的 beta=1.47、1.66、1.83 A-2。对于 H，不需要 beta 项。
Given the electronic charge parameters obtained from a diffraction study of the charge density distribution in a crystal, a mathematical procedure is presented for deriving the electrostatic potential. The procedure allows the mapping of electrostatic potential for a molecule or group of molecules removed from the crystal structure but with each molecule retaining the effects of polarization owing to the original crystal environment. The method is applied for the neurotransmitter gamma-aminobutyric acid. The potential for a gamma-aminobutyric acid molecule is analyzed in terms of a simple model that is suitable for rapid computations concerned with Coulombic molecular interactions. Outside the molecular envelope at 1.2 A from the atomic nuclei, the total potential is well represented by a sum of spherical atom contributions with V(r) = (q/r) + exp(-beta r2). The most important aspherical component in the potential is the dipole contribution from the hydrogen atoms. This can be represented as V(r, phi) = (0.162 cos phi)/(r2 + 0.615). Here, V is in e/A, r is the distance from each nucleus in A, q is the experimentally determined net atomic charge in electron units, and phi is the angle between r and the bond X-H. We obtain beta=1.47, 1.66, 1.83 A-2 for C, N, and O respectively. For H, no term in beta is needed.