Astani Elahe K, Heshmati Emran, Chen Chun-Jung, Hadipour Nasser L
Department of Chemistry, Faculty of Science, Tarbiat Modares University, Tehran, 14115-175, Iran.
Department of Biology, Faculty of Science, Zanjan University, Zanjan, Iran.
J Mol Graph Model. 2016 Jul;68:14-22. doi: 10.1016/j.jmgm.2016.06.002. Epub 2016 Jun 8.
A theoretical study at the level of density functional theory (DFT) was performed to characterize noncovalent intermolecular interactions, especially hydrogen bond interactions, in the active site of enzyme human androsterone sulphotransferase (SULT2A1/ADT). Geometry optimization, interaction energy, (2)H, (14)N, and (17)O electric field gradient (EFG) tensors, (1)H, (13)C, (17)O, and (15)N chemical shielding (CS) tensors, Natural Bonding Orbital (NBO) analysis, and quantum theory of atoms in molecules (QTAIM) analysis of this active site were investigated. It was found that androsterone (ADT) is able to form hydrogen bonds with residues Ser80, Ile82, and His99 of the active site. The interaction energy calculations and NBO analysis revealed that the ADT molecule forms the strongest hydrogen bond with Ser80. Results revealed that ADT interacts with the other residues through electrostatic and Van der Waals interactions. Results showed that these hydrogen bonds influence on the calculated (2)H, (14)N, and (17)O quadrupole coupling constants (QCCs), as well as (1)H, (13)C, (17)O, and (15)N CS tensors. The magnitude of the QCC and CS changes at each nucleus depends directly on its amount of contribution to the hydrogen bond interaction.
在密度泛函理论（DFT）水平上进行了一项理论研究，以表征人雄激素硫酸转移酶（SULT2A1/ADT）酶活性位点中的非共价分子间相互作用，特别是氢键相互作用。研究了该活性位点的几何优化、相互作用能、（2）H、（14）N和（17）O电场梯度（EFG）张量、（1）H、（13）C、（17）O和（15）N化学屏蔽（CS）张量、自然键轨道（NBO）分析以及分子中的原子量子理论（QTAIM）分析。结果发现，雄甾酮（ADT）能够与活性位点的Ser80、Ile82和His99残基形成氢键。相互作用能计算和NBO分析表明，ADT分子与Ser80形成最强的氢键。结果表明，ADT通过静电和范德华相互作用与其他残基相互作用。结果表明，这些氢键会影响计算得到的（2）H、（14）N和（17）O四极耦合常数（QCC）以及（1）H、（13）C、（17）O和（15）N CS张量。每个原子核处QCC和CS变化的大小直接取决于其对氢键相互作用的贡献量。
