| dc.description.abstract | Cell membranes are an essential portion for cells to operate functionally, keep the viability of organisms, and hold abilities to receive, resist, or interact with molecules outside cells. Among the diverse properties of membranes, composition is a crucial one for their biological functions; the rigidity, phases, dynamics, and interaction with peptides are highly related to it. Among these aspects, exploring the latter two may contribute to the understanding of the mechanisms of some neurological diseases. Because of the mobility difference of lipids, compositional variations would modulate membrane dynamics in various spatial scales. On the other hand, we employed amyloid β peptides (Aβ) to investigate the membrane-peptide interaction. According to previous studies, Alzheimer’s disease could be the combined result of Aβ aggregation and oxidative stress, and Aβ-membrane interactions could be different once the composition of membranes was varied by the hydrocarbon chain oxidation. From our inelastic neutron scattering results, we found that membrane dynamics in various spatial scales were highly related to lipids’ molecular configuration in hydrocarbon chains but not in head groups. On the Aβ-membrane interaction aspects, we found that the interaction between membranes and Aβ aggregates was highly related to membrane compositions and the presence of Cu2+. From X-ray scattering and fluorescence data, we knew that Aβ oligomers would provide structural impacts on outer leaflets of membranes by Aβ attachments and shallow insertions. However, membranes retained their structural integrity after the interaction with Aβ aggregates, and compositional variations from oxidative treatments also could not affect the integrity of lipid membranes in the event of Aβ oligomers-membrane interaction. Altogether, we find that the increase of saturation degrees affected their dynamics in wide spatial scales and carry out the structure-disrupting membrane-peptide interactions. | en_US |