Diffusion Studies of Amyloid Beta Peptide in Bicelle

Abstract

We studied the diffusion of amyloid beta peptide(25-35) inside bicelle using Pulse field gradient(PFG) Nuclear Magnetic Resonance(NMR) and molecular dynamics sim- ulations. Amyloid beta peptide(A) is the main constituent of senile plaque in the Alzheimer's disease. The neurotoxic fragment Aβ(25-35) can intercalate into the lipid bilayers and affect the dynamics of bilayers. PFG NMR experiments were conducted for samples Aβ(25-35), bicelle(DMPC/DHPC) and Aβ(25-35) inside bicelle. We cal- culated the diffusion coefficient for Aβ(25-35), bicelle(DMPC/DHPC) and Aβ(25-35) inside bicelle. A linear diffusion pattern was observed for Aβ(25-35) as well as bi- celle alone samples. But when we incorporated Aβ(25-35) into bicelle both systems were following anomalous diffusion . The NMR experiment results were validated by molecular dynamics simulations using the MD package Groningen Machine for Chem- ical Simulations(GROMACS). We did 2-dimensional homonuclear and heteronuclear NMR experiments for studying the structure of Aβ(25-35) in bicelle.