title: Solvent effects on structural and thermochemical properties of p53 tumor-suppressor gene: a molecular modeling approach in drug design.
abstract: The p53 tumor-suppressor protein is a cellular phosphoprotein and a negative regulator of cell growth. Most p53 mutations occur in exons 5-8 within the DNA-binding domain. Therefore, p53 can potentially be targeted with novel drugs designed to bind to a mutation and restore its stability or wild-type conformation. For the current study, Hartree-Fock calculations were used to investigate the solvent-induced effects of five different solvent media (acetone, ethanol, methanol, dimethyl sulfoxide, and water) on the thermochemical parameters and relative energies, and on the multinuclear nuclear magnetic resonance shielding tensors of oxygen, nitrogen, and phosphorus nuclei, of GAT. To understand how the solvent affects the mutation region (the "hot spot") of p53, the relative energies of GAT in selected solvent media were determined. Some biological evidence suggested the structural stabilities of hot spots of GAT have the optimum temperature and solvent type for mutation. All the authors' findings are in accordance with common biological phenomena. Another important objective of this study was to compare the hydration Gibbs free energies of CUA and GAT in water using two different approaches where the solvent was treated as a continuum of the constant at different levels of Hartree-Fock theory. The Gibbs hydration energy values obtained in water with the polarized continuum model directly applied on the isolated CUA and GAT sequences were compared with those determined from the hydrated models with four, six, and eight water molecule clusters around the hot spots uracil and adenine. The clustered structures of water molecules around the hot spots of GAT (in DNA level) and CUA (in transcriptional level) were found to be energetically favored. The results of this study provide a reliable insight into the nature of mutation processes, which is of utmost importance for the study of biochemical structures, and provide a basis for drug design.
authors: Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran.
authors: Shiva
authors: S
authors: Irani
authors: Seyed Mohammad
authors: SM
authors: Atyabi
authors: Houri
authors: H
authors: Mivehchi
authors: Seyed Davar
authors: SD
authors: Siadat
authors: Mohammad Reza
authors: MR
authors: Aghasadeghi
authors: Ali
authors: A
authors: Farhangi
mesh_terms: D001483:Base Sequence; D004247:DNA / Q000737:chemistry* / Q000235:genetics; D004273:DNA, Neoplasm / Q000737:chemistry / Q000235:genetics; D015195:Drug Design; D016158:Genes, p53 / Q000187:drug effects*; D006801:Humans; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008956:Models, Chemical; D056004:Molecular Dynamics Simulation; D009369:Neoplasms / Q000235:genetics; D012997:Solvents; D013816:Thermodynamics; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
chemical_list: D004273:DNA, Neoplasm; D012997:Solvents; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D004247:DNA