Sokalski W A, Keller D A, Ornstein R L, Rein R
Department of Biophysics, Roswell Park Cancer Institute, Buffalo, New York 14263-0001, USA.
J Comput Chem. 1993;14(8):970-6. doi: 10.1002/jcc.540140812.
The defects in atomic monopole models of molecular charge distribution have been analyzed for several model-blocked peptides and compared with accurate quantum chemical values. The results indicate that the angular characteristics of the molecular electrostatic potential around functional groups capable of forming hydrogen bonds can be considerably distorted within various models relying upon isotropic atomic charges only. It is shown that these defects can be corrected by augmenting the atomic point charge models by cumulative atomic multipole moments (CAMMs). Alternatively, sets of off-center atomic point charges could be automatically derived from respective multipoles, providing approximately equivalent corrections. For the first time, correlated atomic multipoles have been calculated for N-acetyl, N'-methylamide-blocked derivatives of glycine, alanine, cysteine, threonine, leucine, lysine, and serine using the MP2 method. The role of the correlation effects in the peptide molecular charge distribution are discussed.
对几种模型封闭肽的分子电荷分布原子单极模型中的缺陷进行了分析，并与精确的量子化学值进行了比较。结果表明，仅依赖各向同性原子电荷的各种模型中，能够形成氢键的官能团周围分子静电势的角度特征可能会被显著扭曲。结果表明，通过用累积原子多极矩（CAMMs）增强原子点电荷模型，可以纠正这些缺陷。或者，可以从相应的多极自动导出偏心原子点电荷集，提供近似等效的校正。首次使用MP2方法计算了甘氨酸、丙氨酸、半胱氨酸、苏氨酸、亮氨酸、赖氨酸和丝氨酸的N-乙酰基、N'-甲基酰胺封闭衍生物的相关原子多极。讨论了相关效应在肽分子电荷分布中的作用。
