Theoretical investigations on the interactions of some drug fragments with guanine and adenine nucleic acid: DFT method, AIM analysis and NBO calculations

Subject Areas :

Hossein Azizi Toupkanloo ¹ , Zoha Rahmani ²

1 - Department of Physics and Chemistry, Faculty of science, University of Neyshabur, Neyshabur, Iran
2 - Department of Chemistry, Computational Quantum Chemistry Laboratory, University of Sistan and Baluchestan,Zahedan, Iran

Received: 2017-11-24 Accepted : 2018-01-21 Published : 2017-11-22

Keywords: interaction energy, Binding Energy, Keywords: &pi, -&pi, stacking, drug fragment,

Abstract :

Density functional theory (DFT), the atoms in molecule (AIM) theory, and natural bond orbital (NBO) analysis were employed to investigate the π-π stacking interactions between some popular drug fragments (DF) including indole (I), benzothiophene (Bt) benzofuran (Bf) and guanine (G), adenine (A). Several stable conformers of present molecules and complexes were optimized at the M062X/6-311++G(d,p) level of theory. The result shows that the IG1 and IA6 has the maximum interaction energy in all of the two G-based and A-based conformers; and order of the adsorption strength is IG1 > BtG6 > BfG1 for G-based complexes and IA6 > BtA6 > BfG6, for A-based complexes. Furthermore, our results show that DFT calculated interaction energies for all present conformers, were found to be in a good agreement with the AIM analysis. In contrast, there is no reasonable linear correlation were observed between NBO analysis and stability of the all studied conformers.