title: Free energy of lipid bilayer defects affected by Alzheimer's disease-associated amyloid-β42 monomers.
abstract: Experimental evidence suggests that the amyloid β-peptide (Aβ) associated with Alzheimer's disease strongly disturbs the integrity of lipid bilayers and cell membranes, as a possible origin of the toxicity of this peptide. Here, we have used molecular dynamics simulations to compute the free energy of membrane pores in the presence and absence of Aβ. The validation of our approach included the calculation of lipid flip-flop waiting times, which were found to agree well with recent experiments, in contrast with an earlier simulation study that apparently overestimated these waiting times. We find that, compared with peptide-free lipid bilayers, attached Aβ42 peptides (i) increase the order parameters of the lipid tails but (ii) decrease the effective width of the hydrophobic region, (iii) reduce the free energy and thus enlarge the density of membrane pores, and (iv) increase the lifetime of pores. A detailed understanding of the interaction of Aβ42 with lipid bilayer membranes may assist in the design of therapeutical strategies against Alzheimer's disease.
authors.affiliation: Theory & Bio-Systems, Max Planck Institute of Colloids and Interfaces , Science Park Golm, D-14424 Potsdam, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Pobandt
authors.forename: Volker
authors.initials: V
authors.lastname: Knecht
mesh_terms: D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry; D000544:Alzheimer Disease / Q000378:metabolism / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D008051:Lipid Bilayers / Q000737:chemistry* / Q000378:metabolism; D056004:Molecular Dynamics Simulation; D058608:Nanopores; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D016229:Amyloid beta-Peptides; D008051:Lipid Bilayers; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42); D015060:1,2-Dipalmitoylphosphatidylcholine