1. Interactions between Amyloid β-barrel and anionic POPG membrane
Chang Zhongwen, Wei Guanghong
Phys. Dept., Fudan Univ., Shanghai, China
Motivation: Alzheimer’s disease (AD) is by far the most predominant illness of old life. It is characterized by neurotics plaques composed primarily of amyloid beta peptide (Aβ), which is a amino acids residue peptide derived from the trans-membrane amyloid precursor protein (APP) during regular cell metabolism. Although the mechanism of normal metabolite going neurotoxic is not clear, numerous reports have provided evidences that the interactions between Aβ peptide and other cellular components, especially membranes, played a key role in the pathogenesis. One of the prevailing dogmas is that the Aβ disturbed the integrity and increased ion flux in artificial lipid and neuronal cells . The mechanism points to Aβ ion channel formation. However, as Aβ localized in the plasma membrane, little detailed structural information exists to indicate how Aβ induces these observed phenomena, which provides the motivation for our study.
Method:
Molecular Dynamics simulation:
OPLS force field in GROMACS software.;
T=310 K;
PH≈7;
Pressure coupling: Semi isotropic.
Result Membrane bilayer
Result Protein barrel
Calculation of secondary structure of protein
Snapshots of BF1 in different time showing the overall disorder of lipids, and adjustment of secondary structure of protein.
Full-insertion group
Partial-insertion group
Standard deviation of P atoms in POPG
Order parameter of POPG in each trajectory
Accumulated water molecules through bilayer
DSSP for AF1
DSSP for BF1
Conclusion and discussion
The barral-like oligomer of Aβ25-35 has strong interaction with anionic membrane bilayer POPG;
A possible model for positive charged peptide Aβ25-35 interacted with POPG is the conformation of Lys-inside Aβ25-35 barrel-like oligomer, which indicates it’s possible that Aβ25-35 forms oligomer after insertion into membrane;