جستجوی مقالات مرتبط با کلیدواژه "alzheimer" در نشریات گروه "شیمی"

This study investigates the reactivity of the beta-amyloid peptide, particularly focusing on its interactions with copper and zinc ions, which are relevant to the progression of Alzheimer's disease. Molecular dynamics simulations were performed to explore the effects of copper and zinc ions on the stability and binding affinity of the peptide. The presence of copper ions was found to decrease the relative stability of peptide. Conformational analysis revealed that copper ions preferentially bind to the N-terminal residues, with a particularly high affinity for His14. The addition of zinc ions reduced the overall binding affinity of copper ions to the peptide but did not significantly alter the strong interaction with His14. Density functional theory (DFT) calculations on the sampled peptide structures provided quantum descriptors, including the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies, which are indicative of reactivity. The results suggest a significant decrease in the reactivity of His14 in the presence of copper ions, with a further reduction observed in the combined presence of both copper and zinc ions. These findings contribute to understanding the molecular mechanisms underlying metal ion-induced conformational changes in beta-amyloid peptides and their role in Alzheimer's disease.

Sodium dodecyl sulfate (SDS) solution is considered a cell membrane mimicking solution. In this study, the effect of the amyloid-beta peptide on the structure and diffusion coefficient of SDS was investigated by molecular dynamics simulation. To control the accuracy of the calculations, a micelle containing 60 molecules of SDS was simulated. The radius of gyration and the moment of inertia of the micelle were calculated and compared with the experimental and simulation results. The results obtained were in good agreement with the experimental and simulation results. The simulations in the presence of amyloid-beta were performed at two concentrations of SDS, below and above the critical micelle concentration. The results showed that as the concentration of SDS increased, the diffusion coefficient of peptide and sodium ion increased while the diffusion coefficient of water and SDS decreased. The calculation of the moments of inertia in different directions showed that the micelles deviated from the ellipsoidal shape at sub-critical micelle concentrations of SDS.

Quantitative structure-activity relationship (QSAR) study on the piperidone-grafted mono- and bis-spirooxindole-hexahydropyrrolizines as potent butyrylcholinestrase (BuChE) inhibitors were carried out using statistical methods, molecular dynamics and molecular docking simulation. QSAR methodologies, including classification and regression tree (CART), multiple linear regression (MLR), principal component analysis (PCA) and principal component regression analysis (PCRA). Three descriptors in three classes: 3D-Morse, WHIM and GETAWAY descriptors were selected by SPSS software and then applied in the final tree structure to describe the inhibitory activities. Docking simulations were carried out using AutoDock Vina softwares for all inhibitors. Docking results showed that the studied BuChE inhibitors have two commons binding modes. Molecular dynamics results obtained by Gromacs showed that the more potent inhibitor has more interaction with the enzyme and higher effect on the enzyme structure.