title: A theoretical study on the characteristics of the intermolecular interactions in the active site of human androsterone sulphotransferase: DFT calculations of NQR and NMR parameters and QTAIM analysis.
abstract: 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.
authors.affiliation: Department of Chemistry, Faculty of Science, Tarbiat Modares University, Tehran, 14115-175, Iran.
authors.forename: Elahe K
authors.initials: EK
authors.lastname: Astani
authors.affiliation: Department of Biology, Faculty of Science, Zanjan University, Zanjan, Iran.
authors.forename: Emran
authors.initials: E
authors.lastname: Heshmati
authors.affiliation: Life Science Group, Scientific Research Division, National Synchrotron Radiation Research Center, Taiwan.
authors.forename: Chun-Jung
authors.initials: CJ
authors.lastname: Chen
authors.affiliation: Department of Chemistry, Faculty of Science, Tarbiat Modares University, Tehran, 14115-175, Iran. Electronic address: hadipour@modares.ac.ir.
authors.forename: Nasser L
authors.initials: NL
authors.lastname: Hadipour
mesh_terms: D000738:Androsterone / Q000737:chemistry; D020134:Catalytic Domain; D004560:Electricity; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D025341:Principal Component Analysis; D011789:Quantum Theory; D015238:Sulfotransferases / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D000738:Androsterone; D015238:Sulfotransferases; C071523:androsterone sulfotransferase
keywords: ADT; Active site; DFT; EFG and CS tensors; NBO and QTAIM analyses; Noncovalent intermolecular interactions; QCC and CS parameters; SULT2A1/ADT