Heparin-Assisted Amyloidogenesis Uncovered through Molecular Dynamics Simulations

Area of Science:

• Biochemistry
• Molecular Biology
• Biophysics

Background:

• Glycosaminoglycans (GAGs), such as heparan sulfate and heparin, are found alongside Aβ amyloid.
• GAGs are known to enhance amyloid fibril formation, suggesting a role in pathological processes.
• Understanding the molecular mechanisms of GAG-mediated fibril enhancement is crucial.

Purpose of the Study:

• To investigate the molecular assembly of the KLVFFA peptide fragment by heparin.
• To elucidate the mechanistic role of GAGs in enhancing peptide fibril formation.
• To gain insights into the design of heparin mimetics and functional GAGs.

Main Methods:

• Molecular dynamics simulations were employed to study heparin's interaction with the KLVFFA peptide.
• Analysis focused on the dynamic process of peptide gathering and assembly mediated by heparin.

Main Results:

• Heparin accelerates peptide assembly through a 'gathering' and subsequent 'assembling' mechanism.
• Heparin forms a tightly coupled composite protofilament structure with peptides, not acting as a mere template.
• Heparin chain flexibility is essential for fibril promotion, with optimal chain length and concentration identified.

Conclusions:

• Heparin's interaction with peptides leads to composite formation, a potentially general feature of GAG-peptide interactions.
• Heparin chain flexibility and optimal concentration/length are critical for its fibril promotion activity.
• The study provides design rules for developing effective heparin mimetics and functional GAGs.