The experimental and model studies on lipid membranes: The coarse-grained MD-simulations of deformed vesicles

The Coarse-Grained (CG) molecular dynamics (MD) simulations were used to simulate the structural behavior of biological membranes. The CG MD simulated models cover the different membrane lipidic vesicle systems with amyloid peptides and/or cholesterol and melatonin molecules. The CG MD technique allows one to considerable extend the accessible size and time in simulations of biological systems such as lipid bilayers, big vesicles, filaments, etc, containing several hundred thousand up to multi-million particles. The structural properties of model lipid membranes (spherical-like vesicles) were studied and MD simulation data were correlated with the experimental ones (the neutron scattering in particular). The molecular systems were designed and studied to associate the experimental and model studies with the nature of the mechanisms of occurrence of Alzheimer's disease. Under certain conditions the amyloid beta oligomer can undergo an incorrect conformational rearrangement leading to the transition of "normal" soluble peptides into a toxic conformation, while causing the formation of filamentous aggregates – insoluble rigid fibrils of large sizes, that are a sign of the disease. However, the toxic effect, which has a destructive effect on the nerve cells of the brain, is possessed already by isolated misfolded peptides born in the cell membrane.