Neutron Scattering Studies of the Interplay of Amyloid β Peptide(1-40) and An Anionic Lipid 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol

The interaction between lipid bilayers and Amyloid beta peptide (A beta) plays a critical role in proliferation of Alzheimer's disease (AD). AD is expected to affect one in every 85 humans by 2050, and therefore, deciphering the interplay of A beta and lipid bilayers at the molecular level is of profound importance. In this work, we applied an array of neutron scattering methods to study the structure and dynamics of A beta(1-40) interacting 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG) bilayers. In the structural investigations of lipid bilayer's response to A beta binding, Small Angle Neutron Scattering and Neutron Membrane Diffraction revealed that the A beta anchors firmly to the highly charged DMPG bilayers in the interfacial region between water and hydrocarbon chain, and it doesn't penetrate deeply into the bilayer. This association mode is substantiated by the dynamics studies with high resolution Quasi-Elastic Neutron Scattering experiments, showing that the addition of A beta mainly affects the slower lateral motion of lipid molecules, especially in the fluid phase, but not the faster internal motion. The results revealed that A beta associates with the highly charged membrane in surface with limited impact on the structure, but the altered membrane dynamics could have more influence on other membrane processes.