posted on 2020-03-19, 11:38authored byValeria Castelletto, Jani Seitsonen, Kunal M. Tewari, Abshar Hasan, Robert M. Edkins, Janne Ruokolainen, Lalit M. Pandey, Ian W. Hamley, King Hang Aaron Lau
Peptoids
are biofunctional N-substituted glycine peptidomimics.
Their self-assembly is of fundamental interest because they demonstrate
alternatives to conventional peptide structures based on backbone
chirality and beta-sheet hydrogen bonding. The search for self-assembling,
water-soluble “minimal” sequences, be they peptide or
peptidomimic, is a further challenge. Such sequences are highly desired
for their compatibility with biomacromolecules and convenient synthesis
for broader application. We report the self-assembly of a set of trimeric,
water-soluble α-peptoids that exhibit a relatively low critical
aggregation concentration (CAC ∼ 0.3 wt %). Cryo-EM and angle-resolved
DLS show different sequence-dependent morphologies, namely uniform
ca. 6 nm wide nanofibers, sheets, and clusters of globular assemblies.
Absorbance and fluorescence spectroscopies indicate unique phenyl
environments for π-interactions in the highly ordered nanofibers.
Assembly of our peptoids takes place when the sequences are fully
ionized, representing a departure from superficially similar amyloid-type
hydrogen-bonded peptide nanostructures and expanding the horizons
of assembly for sequence-specific bio- and biomimetic macromolecules.