1,721,039 research outputs found
Molecular Modeling of CYP2D6 complexes and docking of a series of ajmalicine- and quinidine-like inhibitors
No full textMolecular Modelling of human CYP2D6 and molecular docking of a series of ajmalicine- and quinidine-like inhibitors
No full text3D-models were created and refined for CYP2D6 and for its complexes with ajmalicine and quinidine. The influence of the conformation of the enzyme active site on its interaction with ligands was evaluated by performing three series of molecular docking on selected ajmalicine- and quinidine-like inhibitors. The results suggested that the experimental binding values of ajmalicine- and quinidine-like inhibitors better fit with the energetic terms derived from their interaction with structures of CYP2D6 obtained by, respectively, optimizing the ajmalicine/CYP2D6 and the quinidine/CYP2D6 complexes, rather than exploiting the 3D-strucure of the enzyme not subjected to a ligand-induced conformational change. It suggests the relevance of induced-fit phenomena in the biological system of interest
A modeling study of alphaB-crystallin in complex with zinc for investigating the correlation between chaperone-like activity and exposure of hydrophobic surfaces
No full textThree-dimensional models for alphaB-crystallin and its complex with zinc were obtained by molecular homology modeling and quantum mechanical calculations in order to explain the effect of the metal on the chaperone-like activity of alphaB-crystallin. In fact, measurements of the chaperone-like activity of alphaB-crystallin revealed that it is significantly increased in presence of the zinc. The theoretical models allowed us to estimate the increased exposition of hydrophobic residues caused by the presence of zinc, suggesting a relationship between structural changes and the increased chaperone-like activity
Binding free energy calculations of Adenosine Deaminase inhibitors
No full textThe interactions between four inhibitors and adenosine deaminase (ADA) were examined by calculating their binding free energies after molecular dynamics simulations. A bonded model was used to represent the electrostatic potentials of the zinc coordination site. The charge distribution of the model was derived by using a two-stage electrostatic potential fitting calculations. The calculated binding free energies are in good agreement with the experimental data and the ranking of binding affinities is well reproduced. Notably, our findings suggest that non-polar contributions play an important role for ADA-inhibitor interactions
Structural Studies and Molecular Modeling of alphaB-Crystallin: Effects of Zinc and Temperature
No full textIDENTIFICATION OF "TOXICOPHORIC" FEATURES FOR PREDICTING DRUG-INDUCED QT INTERVAL PROLONGATION
No full textDrugs delaying cardiac repolarization by blockade of hERG K(+) channel generally prolong the QT interval of the electrocardiogram, an effect regarded as a cardiac risk factor with the potential to cause 'torsade des pointes'-type arrhythmias in humans. The present study applied a homology building technique and molecular dynamics simulations to model the pore of hERG K(+) channel. A docking analysis was then performed on selected ligands which were classified as QT-prolonging or non-prolonging after experimental measurements in in vivo anesthetized guinea pig. The results of this structural analysis provided a "toxicophoric" model that was further exploited to inspect a dataset of known QT-prolonging/non-prolonging molecules. The emerging major chemical features to be avoided, in order to obtain cardiac safe therapeutic agents, comprise the simultaneous presence of (i) a protonated nitrogen atom within an observed range of distances from a heteroatom; (ii) aromatic groups capable of interacting within an area defined by Gly657 residues of the pore or within an area located at the top of the longitudinal axis of the pore. Moreover, additional hydrophobic moieties interacting with one of the equatorial cavities located in the area near-by Tyr652 residues and/or with a hydrophobic ring defined by Phe656 residues should be avoided
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