Study of structural stability and damaging effect on membrane for four Aβ42 dimers

Area of Science:

• Neuroscience
• Biochemistry
• Computational Biology

Background:

• Amyloid-beta (Aβ) oligomers are implicated in Alzheimer's disease pathogenesis.
• Aβ dimers represent the smallest toxic aggregate units, making their study crucial.

Purpose of the Study:

• To investigate how different aggregation patterns of Aβ42 dimers affect their structural stability.
• To determine the impact of Aβ42 dimer aggregation patterns on biological membrane disruption.

Main Methods:

• Utilized molecular dynamic simulations to analyze four distinct Aβ42 dimer configurations (2NCb, CNNC, NCNC, NCCN).
• Simulations were conducted within a hydrated dipalmitoylphosphatidylcholine (DPPC) membrane environment.

Main Results:

• Aβ42 dimers NCCN, CNNC, and NCNC exhibited significant N-terminal structural fluctuations, converting β-strands to coil structures.
• This loss of β-strand structure in some dimers reduced their aggregation potential.
• Aβ42 dimer insertion into the DPPC membrane decreased average area per lipid (APL), with effects dependent on dimer location and secondary structure.

Conclusions:

• The 2NCb Aβ42 dimer configuration is identified as a stable unit for forming larger Aβ42 oligomers.
• The 2NCb dimer demonstrates a significant capacity to disrupt biological membranes, highlighting its pathogenic potential in Alzheimer's disease.