Analysis of Physicochemical Interaction of Aβ with a GM1 Ganglioside-Containing Lipid Membrane.

The interaction of amyloid beta (Aβ) peptides with the cell membrane is one of the factors enhancing Aβ aggregation, which is closely related to neurodegenerative disease. In this work, we performed molecular dynamics (MD) simulation to investigate the initial stage of adhesion of Aβ to a GM1 ganglioside-containing membrane. Conformational change of Aβ due to interaction with the membrane was monitored and compared with that of Aβ observed in the previous study. Multiple computational trials were executed to analyze the probability of Aβ binding using a calculation model consisting of a GM1-containing mixed lipid membrane, a water layer, ions, and Aβ. A single long-time MD simulation was also carried out. It was suggested from the simulation that a cluster of sialic acids of GM1 head groups often caught the side chain of His13 or His14 of Aβ in the early stage of the MD simulations. Afterward, the main chain of Leu34 formed many hydrogen bonds with gangliosides. These residues cooperatively work for Aβ to be held on the lipid membrane. It is notable that Aβ was observed to be deeply inserted into the head group region of the lipid membrane in some computational trials. In the insertion, Aβ occasionally formed a hydrogen bond with sphingomyelin. The difference in the secondary structure between Aβ and Aβ was an important factor for Aβ to be deeply inserted into the membrane.