Identifying Heterozipper β-Sheet in Twisted Amyloid Aggregation.

Area of Science:

• Biochemistry
• Materials Science
• Nanotechnology

Background:

• Amyloid peptide self-assembly is crucial for nanostructure formation.
• Understanding the precise mechanisms of amyloid peptide (AP) hierarchical assembly remains a challenge.

Purpose of the Study:

• To elucidate the molecular mechanisms driving AP self-assembly into well-ordered nanostructures.
• To identify the fundamental building units and rules governing hierarchical fibril formation.

Main Methods:

• Atomic Force Microscopy (AFM) for morphological analysis.
• Cryo-Electron Microscopy (cryo-EM) for high-resolution structural determination.
• Molecular Dynamics (MD) simulations for mechanistic insights.

Main Results:

• AP self-assembly results in uniform, twisted fibrils with consistent morphology and periodicity.
• A novel heterozipper beta-sheet structure was identified as a protofilament building block.
• The arrangement of antiparallel beta strands within the heterozipper, driven by hydrophobic and hydrophilic interactions, dictates assembly.

Conclusions:

• This study reveals the fundamental rule governing AP hierarchical assembly into helical fibrils.
• The identified heterozipper beta-sheet structure is the basic unit driving the formation of ordered amyloid nanostructures.