Square channels formed by a peptide derived from transthyretin

Area of Science:

• Biochemistry
• Structural Biology
• Materials Science

Background:

• High-resolution structures of peptide supramolecular assemblies are crucial for understanding amyloid diseases.
• These structures are also vital for designing novel peptide-based materials.
• Transthyretin (TTR) is a protein implicated in amyloidosis, and its β-strands are key to its structure.

Purpose of the Study:

• To explore the supramolecular assembly of a macrocyclic β-sheet peptide derived from transthyretin (TTR).
• To mimic the β-hairpin formed by the G and H β-strands of TTR.
• To investigate the structural outcome of this peptide's self-assembly.

Main Methods:

• Design and synthesis of a macrocyclic peptide mimicking TTR's β-hairpin.
• X-ray crystallography to determine the high-resolution structure of the peptide assembly.

Main Results:

• The peptide did not form the expected tetrameric structure.
• Instead, it self-assembled into unique square channels.
• These channels are formed by extended β-sheet networks with a 'tilted windows' packing pattern.

Conclusions:

• The observed square channel structure is an emergent property of the designed peptide.
• This finding expands the known repertoire of β-sheet supramolecular assemblies.
• Understanding such assemblies could inform strategies for amyloid disease treatment and biomaterial design.