Cooperative hydrogen bonding in amyloid formation

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• Amyloid diseases like Alzheimer's and prion diseases are characterized by protein fibrils.
• These fibrils share properties, including nucleation-dependent growth.
• The initial phase of fibril formation, nucleation, is kinetically slow.

Purpose of the Study:

• To explore the energetics of amyloid fibril formation.
• To investigate the molecular mechanisms underlying nucleation-dependent fibril growth.
• To understand the cooperative nature of early-stage fibril assembly.

Main Methods:

• Utilized classical and quantum (density functional theory) computational methods.
• Focused on the molecular structure of a fibril-forming peptide from yeast prion Sup35.
• Analyzed the energetics of the first three layers of fibril formation.

Main Results:

• Found cooperative energetics for the initial three layers of fibril formation using both computational methods.
• Demonstrated that these cooperative energetics explain the slow nucleation and rapid growth phases.
• Provided energetic insights into the self-assembly of amyloid fibrils.

Conclusions:

• The study supports the hypothesis of nucleation-dependent fibril growth in amyloid diseases.
• Cooperative energetics in early assembly stages are crucial for fibril formation.
• Computational modeling offers valuable insights into the molecular mechanisms of amyloidogenesis.