High-resolution structures of peptide supramolecular assemblies are key to
understanding amyloid diseases and designing peptide-based materials. This paper
explores the supramolecular assembly of a macrocyclic β-sheet peptide derived
from transthyretin (TTR). The peptide mimics the β-hairpin formed by the
β-strands G and H of TTR, which form the interface of the TTR tetramer. X-ray
crystallography reveals that the peptide does not form a tetramer, but rather
assembles to form square channels. The square channels are formed by extended
networks of β-sheets and pack in a "tilted windows" pattern. This
unexpected structure represents an emergent property of the peptide and broadens
the scope of known supramolecular assemblies of β-sheets.
